diff --git a/CHANGELOG.md b/CHANGELOG.md
index 01d0d7ad8..f11ac4725 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -46,6 +46,7 @@
 - MS SQL: Hide table actions and row editing in the sys schema
 - Elasticsearch, ClickHouse: Use default port
 - ClickHouse: Fix nullable columns, fix default values, show server version
+- ClickHouse: Support schema management, introspection and administration
 - MongoDB: Authenticate against the database used in login
 - MongoDB: Do not treat the string NULL as the NULL value
 - MongoDB: Show the primary key column when altering indexes (regression from 5.4.0)
diff --git a/plugins/drivers/clickhouse.php b/plugins/drivers/clickhouse.php
index aa91d8f1d..a6502f207 100644
--- a/plugins/drivers/clickhouse.php
+++ b/plugins/drivers/clickhouse.php
@@ -1,23 +1,35 @@
 <?php
 namespace Adminer;
 
-add_driver("clickhouse", "ClickHouse (alpha)");
+add_driver("clickhouse", "ClickHouse");
 
 if (isset($_GET["clickhouse"])) {
 	define('Adminer\DRIVER', "clickhouse");
 
+	// Adminer couples index display to its generic index editor. ClickHouse
+	// indexes have different semantics, so keep the structure view read-only.
+	if (isset($_GET["indexes"])) {
+		$_GET["table"] = $_GET["indexes"];
+		unset($_GET["indexes"]);
+	}
+
 	if (ini_bool('allow_url_fopen')) {
 		class Db extends SqlDb {
 			public $extension = "JSON";
 			public $_db = 'default';
 			private $url;
+			private $authorization;
 
 			function rootQuery($db, $query) {
-				list($file, $status) = get_url("$this->url/?database=$db", stream_context_create(array('http' => array(
+				$this->error = '';
+				$this->errno = 0;
+				$this->affected_rows = 0;
+				list($file, $status) = get_url($this->url . "/?database=" . rawurlencode($db), stream_context_create(array('http' => array(
 					'method' => 'POST',
 					'content' => $query,
 					'header' => array(
-						'Content-Type: application/x-www-form-urlencoded',
+						'Authorization: Basic ' . $this->authorization,
+						'Content-Type: text/plain; charset=UTF-8',
 						'X-ClickHouse-Format: JSONCompact',
 					),
 					'ignore_errors' => 1,
@@ -25,58 +37,65 @@ function rootQuery($db, $query) {
 					'max_redirects' => 0,
 				))));
 
-				if ($file === false || $status == 403) {
+				if ($status == 401 || $status == 403) {
 					$this->error = lang('Invalid credentials.');
+					$this->errno = $status;
 					return false;
 				}
-				$return = json_decode($file, true);
-				if ($return === null) {
-					if (!$this->isQuerySelectLike($query) && $file === '') {
-						return true;
-					}
-
-					$this->errno = json_last_error();
-					if (function_exists('json_last_error_msg')) {
-						$this->error = json_last_error_msg();
+				if ($file === false) {
+					$lastError = error_get_last();
+					$this->error = ($lastError && $lastError['message']
+						? preg_replace('~^file_get_contents\([^)]*\):\s*~', '', $lastError['message'])
+						: lang('Unable to connect.')
+					);
+					return false;
+				}
+				if ($status < 200 || $status >= 300) {
+					if (preg_match('~Code:\s*(\d+)~', $file, $match)) {
+						$this->errno = (int) $match[1];
 					} else {
-						$constants = get_defined_constants(true);
-						foreach ($constants['json'] as $name => $value) {
-							if ($value == $this->errno && preg_match('~^JSON_ERROR_~', $name)) {
-								$this->error = $name;
-								break;
-							}
-						}
+						$this->errno = (int) $status;
+					}
+					$this->error = trim($file);
+					if ($this->error === '') {
+						$this->error = "ClickHouse HTTP error $status.";
 					}
+					return false;
+				}
+
+				if (trim($file) === '') {
+					return true;
 				}
-				// 400 == Syntax error
-				// 404 == Unknown expression identifier
-				// 500 == Column 'x' is not under aggregate function and not in GROUP BY keys
-				if (preg_match('~^[45]~', $status)) {
-					$this->error = $return['exception'];
+
+				$return = json_decode($file, true);
+				if (!is_array($return) || !isset($return['data']) || !isset($return['meta'])) {
+					$this->errno = json_last_error();
+					$this->error = ($this->errno && function_exists('json_last_error_msg')
+						? json_last_error_msg()
+						: 'Unexpected response returned by ClickHouse.'
+					);
 					return false;
 				}
 				return new Result($return);
 			}
 
-			function isQuerySelectLike($query) {
-				return (bool) preg_match('~^\s*(select|show|with)~i', $query);
-			}
-
 			function query($query, $unbuffered = false) {
+				if (preg_match('~^\s*USE\s+(?:`((?:``|[^`])+)`|([A-Za-z_][A-Za-z0-9_]*))\s*;?\s*$~i', $query, $match)) {
+					$this->_db = str_replace("``", "`", ($match[1] !== '' ? $match[1] : $match[2]));
+					return true;
+				}
 				return $this->rootQuery($this->_db, $query);
 			}
 
 			function attach($server, $username, $password): string {
-				preg_match('~^(https?://)?(.*)~', $server, $match);
-				if (!strpos($match[2], ":")) {
-					$match[2] .= ":8123";
-				}
-				$this->url = ($match[1] ?: "http://") . urlencode($username) . ":" . urlencode($password) . "@$match[2]";
-				$version = get_val('SELECT version()', 0, $this); // also verifies the connection
-				if ($version === false) {
+				$this->url = rtrim((preg_match('~^https?://~i', $server) ? $server : "http://$server"), '/');
+				$this->authorization = base64_encode("$username:$password");
+				$return = $this->query('SELECT version()');
+				if (!$return) {
 					return $this->error;
 				}
-				$this->server_info = $version;
+				$row = $return->fetch_row();
+				$this->server_info = ($row ? $row[0] : '');
 				return '';
 			}
 
@@ -86,52 +105,77 @@ function select_db($database) {
 			}
 
 			function quote($string): string {
-				return "'" . addcslashes($string, "\\'") . "'";
+				return "'" . strtr($string, array(
+					"\\" => "\\\\",
+					"'" => "\\'",
+					"\0" => "\\0",
+					"\b" => "\\b",
+					"\f" => "\\f",
+					"\n" => "\\n",
+					"\r" => "\\r",
+					"\t" => "\\t",
+				)) . "'";
 			}
 		}
 
 		class Result {
 			public $num_rows, $columns, $meta;
-			private $rows = array(), $offset = 0;
+			private $rows = array(), $rowOffset = 0, $fieldOffset = 0;
 
 			function __construct($result) {
-				foreach ($result['data'] as $item) {
+				$this->meta = (array) $result['meta'];
+				foreach ((array) $result['data'] as $item) {
 					$row = array();
-					foreach ($item as $key => $val) {
-						$row[$key] = is_scalar($val) ? $val : json_encode($val, 256); // 256 - JSON_UNESCAPED_UNICODE available since PHP 5.4
+					foreach ((array) $item as $key => $val) {
+						$type = (isset($this->meta[$key]['type']) ? $this->meta[$key]['type'] : '');
+						$row[$key] = ($val === null || is_scalar($val)
+							? $this->normalizeValue($val, $type)
+							: json_encode($val, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES)
+						);
 					}
 					$this->rows[] = $row;
 				}
-				$this->num_rows = $result['rows'];
-				$this->meta = $result['meta'];
+				$this->num_rows = (isset($result['rows']) ? $result['rows'] : count($this->rows));
 				$this->columns = array_map(function ($column) {
 					return $column['name'];
 				}, $this->meta); // array_column() is available since PHP 5.5
-				reset($this->rows);
+			}
+
+			private function normalizeValue($value, $type) {
+				// FixedString is NUL-padded to its declared width. The padding is
+				// storage detail rather than user data and breaks Adminer links and
+				// form controls if it is allowed through to the HTML response.
+				if (is_string($value) && preg_match('~(?:^|\()FixedString\(\d+\)~', $type)) {
+					return rtrim($value, "\0");
+				}
+				return $value;
 			}
 
 			function fetch_assoc() {
-				$row = current($this->rows);
-				next($this->rows);
-				return $row === false ? false : array_combine($this->columns, $row);
+				if (!isset($this->rows[$this->rowOffset])) {
+					return false;
+				}
+				return array_combine($this->columns, $this->rows[$this->rowOffset++]);
 			}
 
 			function fetch_row() {
-				$row = current($this->rows);
-				next($this->rows);
-				return $row;
+				return (isset($this->rows[$this->rowOffset]) ? $this->rows[$this->rowOffset++] : false);
 			}
 
 			function fetch_field(): \stdClass {
-				$column = $this->offset++;
+				$column = $this->fieldOffset++;
 				$return = new \stdClass;
 				if ($column < count($this->columns)) {
 					$return->name = $this->meta[$column]['name'];
-					$return->type = $this->meta[$column]['type']; //! map to MySQL numbers
+					$return->type = $this->meta[$column]['type'];
 					$return->charsetnr = 0;
 				}
 				return $return;
 			}
+
+			function seek($offset) {
+				$this->rowOffset = max(0, (int) $offset);
+			}
 		}
 	}
 
@@ -139,31 +183,82 @@ class Driver extends SqlDriver {
 		static $extensions = array("allow_url_fopen");
 		static $jush = "clickhouse";
 
-		public $operators = array("=", "<", ">", "<=", ">=", "!=", "~", "!~", "LIKE", "LIKE %%", "IN", "IS NULL", "NOT LIKE", "NOT IN", "IS NOT NULL", "SQL");
+		public $operators = array("=", "<", ">", "<=", ">=", "!=", "LIKE", "LIKE %%", "ILIKE", "ILIKE %%", "IN", "IS NULL", "NOT LIKE", "NOT ILIKE", "NOT IN", "IS NOT NULL", "SQL");
+		public $functions = array("length", "lower", "round", "toDate", "toDateTime", "toString", "upper");
 		public $grouping = array("avg", "count", "count distinct", "max", "min", "sum");
+		public $insertFunctions = array("Date|DateTime" => "now");
+		public $editFunctions = array(
+			"Int|UInt|Float|Decimal" => "+/-",
+			"String|FixedString" => "concat",
+		);
+		public $generated = array("MATERIALIZED", "ALIAS", "EPHEMERAL");
 
 		static function connect($server, $username, $password) {
-			if (!preg_match('~^(https?://)?[-a-z\d.]+(:\d+)?$~', $server)) {
+			$url = (preg_match('~^https?://~i', $server) ? $server : "http://$server");
+			$parts = @parse_url($url);
+			if (
+				!is_array($parts)
+				|| !isset($parts['scheme'], $parts['host'])
+				|| !in_array(strtolower($parts['scheme']), array('http', 'https'), true)
+				|| isset($parts['user']) || isset($parts['pass']) || isset($parts['query']) || isset($parts['fragment'])
+				|| (isset($parts['path']) && $parts['path'] !== '' && $parts['path'] !== '/')
+			) {
 				return lang('Invalid server.');
 			}
 			return parent::connect($server, $username, $password);
 		}
 
+		function hasCStyleEscapes(): bool {
+			return true;
+		}
+
 		function __construct(Db $connection) {
 			parent::__construct($connection);
-			$this->types = array( //! arrays
+			$this->types = array(
 				lang('Numbers') => array(
 					"Int8" => 3, "Int16" => 5, "Int32" => 10, "Int64" => 19,
 					"UInt8" => 3, "UInt16" => 5, "UInt32" => 10, "UInt64" => 20,
-					"Float32" => 7, "Float64" => 16,
-					'Decimal' => 38, 'Decimal32' => 9, 'Decimal64' => 18, 'Decimal128' => 38,
+					"Int128" => 39, "Int256" => 78, "UInt128" => 39, "UInt256" => 78,
+					"Float32" => 14, "Float64" => 23, "BFloat16" => 7, "Bool" => 1,
+					"Decimal" => 76, "Decimal32" => 9, "Decimal64" => 18,
+					"Decimal128" => 38, "Decimal256" => 76,
+				),
+				lang('Date and time') => array(
+					"Date" => 10, "Date32" => 10, "DateTime" => 19, "DateTime64" => 29,
+				),
+				lang('Strings') => array("String" => 0, "FixedString" => 0),
+				lang('Other') => array(
+					"UUID" => 36, "IPv4" => 15, "IPv6" => 39,
+					"Enum8" => 0, "Enum16" => 0, "Array" => 0, "Map" => 0,
+					"Tuple" => 0, "Nested" => 0, "LowCardinality" => 0,
+					"AggregateFunction" => 0, "SimpleAggregateFunction" => 0,
+					"Variant" => 0, "Dynamic" => 0, "JSON" => 0,
 				),
-				lang('Date and time') => array("Date" => 13, "DateTime" => 20),
-				lang('Strings') => array("String" => 0),
-				lang('Binary') => array("FixedString" => 0),
 			);
 		}
 
+		function engines(): array {
+			$engines = get_vals("SELECT name FROM system.table_engines ORDER BY name");
+			return ($engines ?: array("MergeTree", "ReplacingMergeTree", "Memory", "Log", "TinyLog"));
+		}
+
+		function allFields() {
+			$return = array();
+			$rows = get_rows(
+				"SELECT c." . idf_escape('table') . " AS " . idf_escape('table')
+				. ", c.name, c.type, c.default_kind, c.default_expression, c.comment, "
+				. "c.is_in_primary_key, c.is_in_sorting_key, t.engine AS table_engine "
+				. "FROM system.columns AS c LEFT JOIN system.tables AS t "
+				. "ON c.database = t.database AND c." . idf_escape('table') . " = t.name "
+				. "WHERE c.database = " . q($this->conn->_db)
+				. " ORDER BY c." . idf_escape('table') . ", c.position"
+			);
+			foreach ($rows as $row) {
+				$return[$row['table']][] = clickhouse_field($row);
+			}
+			return $return;
+		}
+
 		function delete($table, $queryWhere, $limit = 0) {
 			if ($queryWhere === '') {
 				$queryWhere = 'WHERE 1=1';
@@ -179,6 +274,14 @@ function update($table, array $set, $queryWhere, $limit = 0, $separator = "\n")
 			$query = $separator . implode(",$separator", $values);
 			return queries("ALTER TABLE " . table($table) . " UPDATE $query$queryWhere");
 		}
+
+		function insert($table, array $set) {
+			if (!$set) {
+				$this->conn->error = 'ClickHouse does not support DEFAULT VALUES without an explicit column list.';
+				return false;
+			}
+			return parent::insert($table, $set);
+		}
 	}
 
 	function idf_escape($idf) {
@@ -189,55 +292,161 @@ function table($idf) {
 		return idf_escape($idf);
 	}
 
+	function clickhouse_qualified($database, $name) {
+		return idf_escape($database) . "." . idf_escape($name);
+	}
+
+	function clickhouse_type_info($fullType) {
+		$fullType = trim($fullType);
+		$type = $fullType;
+		$nullable = false;
+		if (preg_match('~^Nullable\((.*)\)$~s', $type, $match)) {
+			$nullable = true;
+			$type = $match[1];
+		}
+		if (preg_match('~^([A-Za-z][A-Za-z0-9_]*)(?:\((.*)\))?$~s', $type, $match)) {
+			return array($match[1], isset($match[2]) ? $match[2] : '', $nullable);
+		}
+		return array($type, '', $nullable);
+	}
+
+	function clickhouse_default_value($expression) {
+		if (preg_match("~^'(.*)'$~s", $expression, $match)) {
+			return stripcslashes(str_replace("''", "'", $match[1]));
+		}
+		return $expression;
+	}
+
+	function clickhouse_field($row) {
+		list($type, $length, $nullable) = clickhouse_type_info($row['type']);
+		$defaultKind = strtoupper(trim($row['default_kind']));
+		$generated = (in_array($defaultKind, array("MATERIALIZED", "ALIAS", "EPHEMERAL"), true)
+			? $defaultKind
+			: ''
+		);
+		$engine = (isset($row['table_engine']) ? $row['table_engine'] : '');
+		$isView = (bool) preg_match('~View$~', $engine);
+		$privileges = array("select" => 1, "where" => 1, "order" => 1);
+		if (!$generated && !$isView) {
+			$privileges["insert"] = 1;
+		}
+		if (!$generated && preg_match('~MergeTree$~', $engine)) {
+			$privileges["update"] = 1;
+		}
+		return array(
+			"field" => trim($row['name']),
+			"full_type" => trim($row['type']),
+			"type" => $type,
+			"length" => $length,
+			"default" => ($defaultKind ? clickhouse_default_value(trim($row['default_expression'])) : null),
+			"null" => $nullable,
+			"auto_increment" => false,
+			"on_update" => "",
+			"collation" => "",
+			"privileges" => $privileges,
+			"comment" => trim($row['comment']),
+			"primary" => false, // ClickHouse primary keys do not guarantee uniqueness.
+			"generated" => $generated,
+		);
+	}
+
+	function clickhouse_field_definition($parts) {
+		$name = $parts[0];
+		$type = trim($parts[1]);
+		if (isset($parts[2]) && trim($parts[2]) === "NULL" && strpos($type, 'Nullable(') !== 0) {
+			$type = "Nullable($type)";
+		}
+		$default = (isset($parts[3]) ? $parts[3] : '');
+		if (preg_match('~^\s*GENERATED ALWAYS AS \((.*)\)\s+(MATERIALIZED|ALIAS|EPHEMERAL)\s*$~s', $default, $match)) {
+			$default = " $match[2] $match[1]";
+		}
+		$comment = (isset($parts[5]) && preg_match('~^\s*COMMENT\b~i', $parts[5])
+			? $parts[5]
+			: (isset($parts[4]) && preg_match('~^\s*COMMENT\b~i', $parts[4]) ? $parts[4] : '')
+		);
+		return "$name $type$default$comment";
+	}
+
 	function explain($connection, $query) {
-		return '';
+		return $connection->query("EXPLAIN $query");
 	}
 
 	function found_rows($table_status, $where) {
-		$rows = get_vals("SELECT COUNT(*) FROM " . idf_escape($table_status["Name"]) . ($where ? " WHERE " . implode(" AND ", $where) : ""));
-		return empty($rows) ? false : $rows[0];
+		return get_val("SELECT count() FROM " . table($table_status["Name"]) . ($where ? " WHERE " . implode(" AND ", $where) : ""));
 	}
 
 	function alter_table($table, $name, $fields, $foreign, $comment, $engine, $collation, $auto_increment, $partitioning) {
-		$alter = $order = $remove = array();
-		foreach ($fields as $field) {
-			if ($field[1][2] === " NULL") {
-				$field[1][1] = " Nullable(" . ltrim($field[1][1]) . ")"; // NULL is not allowed after the type
-				$field[1][2] = '';
-			} elseif ($field[1][2] === ' NOT NULL') {
-				$field[1][2] = '';
+		if ($table === "") {
+			$definitions = array();
+			foreach ($fields as $field) {
+				if (!empty($field[1])) {
+					$definitions[] = clickhouse_field_definition($field[1]);
+				}
 			}
-
-			if ($field[1] && $field[1][3] == "" && $table != "" && $field[0] != "" && min_version("20.10")) {
-				// MODIFY COLUMN without DEFAULT keeps the original default value
-				$remove[] = "MODIFY COLUMN " . idf_escape($field[0]) . " REMOVE DEFAULT";
+			$engine = ($engine ?: "MergeTree");
+			if (!preg_match('~^[A-Za-z][A-Za-z0-9_]*$~', $engine)) {
+				connection()->error = 'Invalid ClickHouse table engine.';
+				return false;
 			}
+			$status = " ENGINE = $engine";
+			if (preg_match('~MergeTree$~', $engine)) {
+				$status .= " ORDER BY tuple()";
+			}
+			$result = queries("CREATE TABLE " . table($name) . " (\n" . implode(",\n", $definitions) . "\n)$status");
+			if ($result && $comment !== null && $comment !== '') {
+				$result = queries("ALTER TABLE " . table($name) . " MODIFY COMMENT " . q($comment));
+			}
+			return $result;
+		}
 
-			$alter[] = ($field[1]
-				? ($table != "" ? ($field[0] != "" ? "MODIFY COLUMN " : "ADD COLUMN ") : " ") . implode($field[1])
-				: "DROP COLUMN " . idf_escape($field[0])
-			);
-
-			$order[] = $field[1][0];
+		if ($foreign) {
+			connection()->error = 'ClickHouse does not support foreign keys.';
+			return false;
+		}
+		if ($engine !== '') {
+			connection()->error = 'ClickHouse cannot change a table engine with ALTER TABLE.';
+			return false;
+		}
+		if ($collation !== '' || $auto_increment !== '') {
+			connection()->error = 'ClickHouse does not support table collations or auto-increment values.';
+			return false;
 		}
 
-		$alter = array_merge($alter, $remove, $foreign);
-		$status = ($engine ? " ENGINE " . $engine : "");
-		if ($table == "") {
-			return queries("CREATE TABLE " . table($name) . " (\n" . implode(",\n", $alter) . "\n)$status$partitioning" . ' ORDER BY (' . implode(',', $order) . ')');
+		if ($table !== $name) {
+			if (!queries("RENAME TABLE " . table($table) . " TO " . table($name))) {
+				return false;
+			}
+			$table = $name;
 		}
-		if ($table != $name) {
-			$result = queries("RENAME TABLE " . table($table) . " TO " . table($name));
-			if ($alter) {
-				$table = $name;
-			} else {
-				return $result;
+
+		$result = true;
+		foreach ($fields as $field) {
+			if (empty($field[1])) {
+				$result = queries("ALTER TABLE " . table($table) . " DROP COLUMN " . idf_escape($field[0]));
+				if (!$result) {
+					return false;
+				}
+				continue;
+			}
+
+			$newName = $field[1][0];
+			if ($field[0] !== "" && idf_escape($field[0]) !== $newName) {
+				if (!queries("ALTER TABLE " . table($table) . " RENAME COLUMN " . idf_escape($field[0]) . " TO $newName")) {
+					return false;
+				}
+			}
+			$operation = ($field[0] === "" ? "ADD COLUMN" : "MODIFY COLUMN");
+			$order = (isset($field[2]) ? $field[2] : '');
+			$result = queries("ALTER TABLE " . table($table) . " $operation " . clickhouse_field_definition($field[1]) . $order);
+			if (!$result) {
+				return false;
 			}
 		}
-		if ($status) {
-			$alter[] = ltrim($status);
+
+		if ($comment !== null) {
+			$result = queries("ALTER TABLE " . table($table) . " MODIFY COMMENT " . q($comment));
 		}
-		return ($alter || $partitioning ? queries("ALTER TABLE " . table($table) . "\n" . implode(",\n", $alter) . $partitioning) : true);
+		return $result;
 	}
 
 	function truncate_tables($tables) {
@@ -245,7 +454,7 @@ function truncate_tables($tables) {
 	}
 
 	function drop_views($views) {
-		return drop_tables($views);
+		return apply_queries("DROP VIEW", $views);
 	}
 
 	function drop_tables($tables) {
@@ -253,18 +462,18 @@ function drop_tables($tables) {
 	}
 
 	function get_databases($flush) {
-		$result = get_rows('SHOW DATABASES');
-
-		$return = array();
-		foreach ($result as $row) {
-			$return[] = $row['name'];
+		$return = get_session("dbs");
+		if ($flush || $return === null) {
+			$return = get_vals("SELECT name FROM system.databases ORDER BY name");
+			restart_session();
+			set_session("dbs", $return);
+			stop_session();
 		}
-		sort($return);
 		return $return;
 	}
 
 	function limit($query, $where, $limit, $offset = 0, $separator = " ") {
-		return " $query$where" . ($limit ? $separator . "LIMIT " . ($offset ? "$offset, " : "") . $limit : "");
+		return " $query$where" . ($limit ? $separator . "LIMIT $limit" . ($offset ? " OFFSET $offset" : "") : "");
 	}
 
 	function limit1($table, $query, $where, $separator = "\n") {
@@ -272,41 +481,69 @@ function limit1($table, $query, $where, $separator = "\n") {
 	}
 
 	function db_collation($db, $collations) {
+		return null;
 	}
 
 	function logged_user() {
-		$credentials = adminer()->credentials();
-		return $credentials[1];
+		return get_val("SELECT currentUser()");
 	}
 
 	function tables_list() {
-		$result = get_rows('SHOW TABLES');
+		$result = get_rows(
+			"SELECT name, engine FROM system.tables WHERE database = " . q(connection()->_db) . " ORDER BY name"
+		);
 		$return = array();
 		foreach ($result as $row) {
-			$return[$row['name']] = 'table';
+			$return[$row['name']] = ($row['engine'] === 'View' ? 'VIEW' : 'TABLE');
 		}
-		ksort($return);
 		return $return;
 	}
 
 	function count_tables($databases) {
-		return array();
+		$return = array_fill_keys($databases, 0);
+		if (!$databases) {
+			return $return;
+		}
+		$quoted = array_map('Adminer\q', $databases);
+		foreach (
+			get_rows(
+				"SELECT database, count() AS tables FROM system.tables "
+				. "WHERE database IN (" . implode(", ", $quoted) . ") GROUP BY database"
+			) as $row
+		) {
+			$return[$row['database']] = $row['tables'];
+		}
+		return $return;
 	}
 
 	function table_status($name = "", $fast = false) {
 		$return = array();
-		$tables = get_rows("SELECT name, engine FROM system.tables WHERE database = " . q(connection()->_db) . ($name != "" ? " AND name = " . q($name) : ""));
-		foreach ($tables as $table) {
-			$return[$table['name']] = array(
-				'Name' => $table['name'],
-				'Engine' => $table['engine'],
+		$tables = get_rows(
+			"SELECT name, engine, total_rows, total_bytes, comment, sorting_key "
+			. "FROM system.tables WHERE database = " . q(connection()->_db)
+			. ($name != "" ? " AND name = " . q($name) : " ORDER BY name")
+		);
+		foreach ($tables as $row) {
+			$return[$row['name']] = array(
+				'Name' => $row['name'],
+				'Engine' => $row['engine'],
+				'Comment' => $row['comment'],
+				'Rows' => $row['total_rows'],
+				'Data_length' => $row['total_bytes'],
+				'Index_length' => 0,
+				'Data_free' => 0,
+				'Auto_increment' => '',
+				'Collation' => '',
+				'Create_options' => ($row['sorting_key'] ? "ORDER BY $row[sorting_key]" : ''),
 			);
 		}
 		return $return;
 	}
 
 	function is_view($table_status) {
-		return false;
+		// Adminer's generic editor can safely replace ordinary views. Materialized
+		// views need ClickHouse-specific ENGINE/TO clauses, so expose them as tables.
+		return $table_status['Engine'] === 'View';
 	}
 
 	function fk_support($table_status) {
@@ -317,56 +554,241 @@ function convert_field($field) {
 	}
 
 	function unconvert_field($field, $return) {
-		if (in_array($field['type'], array("Int8", "Int16", "Int32", "Int64", "UInt8", "UInt16", "UInt32", "UInt64", "Float32", "Float64"))) {
-			return "to$field[type]($return)";
+		if ($return !== "NULL" && in_array($field['type'], array("Array", "Map", "Tuple"), true)) {
+			return "JSONExtract($return, " . q($field['full_type']) . ")";
+		}
+		if ($return !== "NULL" && $field['full_type'] !== "String") {
+			return "CAST($return AS $field[full_type])";
 		}
 		return $return;
 	}
 
 	function fields($table) {
 		$return = array();
-		$result = get_rows("SELECT name, type, default_expression FROM system.columns WHERE " . idf_escape('table') . " = " . q($table));
+		$result = get_rows(
+			"SELECT c.name, c.type, c.default_kind, c.default_expression, c.comment, "
+			. "c.is_in_primary_key, c.is_in_sorting_key, t.engine AS table_engine "
+			. "FROM system.columns AS c LEFT JOIN system.tables AS t "
+			. "ON c.database = t.database AND c." . idf_escape('table') . " = t.name "
+			. "WHERE c.database = " . q(connection()->_db)
+			. " AND c." . idf_escape('table') . " = " . q($table)
+			. " ORDER BY c.position"
+		);
 		foreach ($result as $row) {
-			$type = trim($row['type']);
-			$nullable = preg_match('~^Nullable\((.+)\)$~', $type, $match);
-			if ($nullable) {
-				$type = $match[1]; // the NULL checkbox is displayed instead
+			$return[trim($row['name'])] = clickhouse_field($row);
+		}
+		return $return;
+	}
+
+	function indexes($table, $connection2 = null) {
+		// Only expose these on the structure page. ClickHouse primary and sorting
+		// keys are not unique, so returning them during row editing would make
+		// Adminer build unsafe, incomplete WHERE clauses.
+		if (!isset($_GET["table"])) {
+			return array();
+		}
+
+		$conn = connection($connection2);
+		$return = array();
+		$rows = get_rows(
+			"SELECT primary_key, sorting_key FROM system.tables "
+			. "WHERE database = " . q($conn->_db) . " AND name = " . q($table),
+			$connection2
+		);
+		if ($rows) {
+			$row = $rows[0];
+			if ($row["primary_key"] !== "") {
+				$return["PRIMARY KEY"] = clickhouse_index("PRIMARY", $row["primary_key"]);
+			}
+			if ($row["sorting_key"] !== "" && $row["sorting_key"] !== $row["primary_key"]) {
+				$return["SORTING KEY"] = clickhouse_index("SORTING KEY", $row["sorting_key"]);
 			}
-			$default = trim($row['default_expression']);
-			$return[trim($row['name'])] = array(
-				"field" => trim($row['name']),
-				"full_type" => $type,
-				"type" => $type,
-				"default" => ($default != "" ? preg_replace("~^'(.*)'$~", '$1', $default) : null), // null - no default value
-				"null" => $nullable,
-				"auto_increment" => '0',
-				"privileges" => array("insert" => 1, "select" => 1, "update" => 0, "where" => 1, "order" => 1),
-			);
 		}
 
+		if (get_val("EXISTS TABLE system.data_skipping_indices", 0, $connection2)) {
+			$rows = get_rows(
+				"SELECT name, expr, type_full, granularity FROM system.data_skipping_indices "
+				. "WHERE database = " . q($conn->_db) . " AND " . idf_escape('table') . " = " . q($table)
+				. " ORDER BY name",
+				$connection2
+			);
+			foreach ($rows as $row) {
+				$definition = "$row[expr] TYPE $row[type_full] GRANULARITY $row[granularity]";
+				$return[$row["name"]] = clickhouse_index("INDEX", $definition);
+			}
+		}
 		return $return;
 	}
 
-	function indexes($table, $connection2 = null) {
-		return array();
+	function clickhouse_index($type, $definition) {
+		return array(
+			"type" => $type,
+			"columns" => array($definition),
+			"lengths" => array(null),
+			"descs" => array(null),
+			"algorithm" => "",
+			"partial" => "",
+		);
+	}
+
+	function alter_indexes($table, $alter) {
+		connection()->error = 'ClickHouse index editing is disabled in Adminer; use the SQL command page.';
+		return false;
 	}
 
 	function foreign_keys($table) {
 		return array();
 	}
 
+	function view($name) {
+		$create = get_val(
+			"SELECT create_table_query FROM system.tables WHERE database = " . q(connection()->_db)
+			. " AND name = " . q($name)
+		);
+		if (preg_match('~\s+AS\s+(?=(?:SELECT|WITH)\b)~i', $create, $match, PREG_OFFSET_CAPTURE)) {
+			$offset = $match[0][1] + strlen($match[0][0]);
+			return array("select" => substr($create, $offset));
+		}
+		return array("select" => "");
+	}
+
 	function collations() {
 		return array();
 	}
 
 	function information_schema($db) {
-		return false;
+		return in_array($db, array("system", "information_schema", "INFORMATION_SCHEMA"), true);
 	}
 
 	function error() {
 		return h(connection()->error);
 	}
 
+	function create_database($db, $collation) {
+		$return = queries("CREATE DATABASE " . idf_escape($db));
+		if ($return) {
+			restart_session();
+			set_session("dbs", null);
+		}
+		return $return;
+	}
+
+	function drop_databases($databases) {
+		$return = apply_queries("DROP DATABASE", $databases, 'Adminer\idf_escape');
+		restart_session();
+		set_session("dbs", null);
+		return $return;
+	}
+
+	function rename_database($name, $collation) {
+		$return = queries("RENAME DATABASE " . idf_escape(connection()->_db) . " TO " . idf_escape($name));
+		if ($return) {
+			connection()->_db = $name;
+			restart_session();
+			set_session("dbs", null);
+		}
+		return (bool) $return;
+	}
+
+	function move_tables($tables, $views, $target) {
+		$source = connection()->_db;
+		foreach (array_merge($tables, $views) as $name) {
+			if (
+				!queries(
+					"RENAME TABLE " . clickhouse_qualified($source, $name)
+					. " TO " . clickhouse_qualified($target, $name)
+				)
+			) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	function copy_tables($tables, $views, $target) {
+		$source = connection()->_db;
+		$overwrite = !empty($_POST["overwrite"]);
+		foreach ($tables as $name) {
+			$destination = clickhouse_qualified($target, $name);
+			if (
+				($overwrite && !queries("DROP TABLE IF EXISTS $destination"))
+				|| !queries("CREATE TABLE $destination AS " . clickhouse_qualified($source, $name))
+				|| !queries("INSERT INTO $destination SELECT * FROM " . clickhouse_qualified($source, $name))
+			) {
+				return false;
+			}
+		}
+		foreach ($views as $name) {
+			$destination = clickhouse_qualified($target, $name);
+			$definition = view($name);
+			if (
+				($overwrite && !queries("DROP VIEW IF EXISTS $destination"))
+				|| !$definition["select"]
+				|| !queries("CREATE VIEW $destination AS $definition[select]")
+			) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	function create_sql($table, $auto_increment, $style) {
+		return get_val(
+			"SELECT create_table_query FROM system.tables WHERE database = " . q(connection()->_db)
+			. " AND name = " . q($table)
+		);
+	}
+
+	function truncate_sql($table) {
+		return "TRUNCATE TABLE " . table($table);
+	}
+
+	function use_sql($database, $style = "") {
+		$name = idf_escape($database);
+		$return = "";
+		if (preg_match('~CREATE~', $style)) {
+			if ($style === "DROP+CREATE") {
+				$return .= "DROP DATABASE IF EXISTS $name;\n";
+			}
+			$return .= "CREATE DATABASE IF NOT EXISTS $name;\n";
+		}
+		return $return . "USE $name";
+	}
+
+	function show_variables() {
+		return get_rows(
+			"SELECT name, value, changed, description FROM system.settings ORDER BY name"
+		);
+	}
+
+	function show_status() {
+		return get_rows(
+			"SELECT metric AS name, toString(value) AS value, description "
+			. "FROM system.metrics ORDER BY metric"
+		);
+	}
+
+	function process_list() {
+		return get_rows(
+			"SELECT query_id AS pid, user, address, elapsed, read_rows, read_bytes, "
+			. "written_rows, written_bytes, memory_usage, query "
+			. "FROM system.processes ORDER BY elapsed DESC"
+		);
+	}
+
+	function kill_process($id) {
+		return queries("KILL QUERY WHERE query_id = " . q($id) . " SYNC");
+	}
+
+	function connection_id() {
+		return "SELECT query_id FROM system.processes WHERE query_id != '' ORDER BY elapsed DESC LIMIT 1";
+	}
+
+	function max_connections() {
+		$value = get_val("SELECT value FROM system.settings WHERE name = 'max_concurrent_queries'");
+		return ($value === false ? "0" : $value);
+	}
+
 	function types(): array {
 		return array();
 	}
@@ -380,6 +802,12 @@ function last_id($result) {
 	}
 
 	function support($feature) {
-		return preg_match("~^(columns|sql|status|table|drop_col)$~", $feature);
+		if ($feature === "indexes") {
+			return isset($_GET["table"]);
+		}
+		return (bool) preg_match(
+			"~^(columns|comment|copy|database|drop_col|dump|kill|move_col|processlist|sql|status|table|variables|view)$~",
+			$feature
+		);
 	}
 }