1 <?php

     2 /**

     3  * Meta API: WP_Meta_Query class

     4  *

     5  * @package WordPress

     6  * @subpackage Meta

     7  * @since 4.4.0

     8  */

     9 

    10 /**

    11  * Core class used to implement meta queries for the Meta API.

    12  *

    13  * Used for generating SQL clauses that filter a primary query according to metadata keys and values.

    14  *

    15  * WP_Meta_Query is a helper that allows primary query classes, such as WP_Query and WP_User_Query,

    16  *

    17  * to filter their results by object metadata, by generating `JOIN` and `WHERE` subclauses to be attached

    18  * to the primary SQL query string.

    19  *

    20  * @since 3.2.0

    21  */

    22 class WP_Meta_Query {

    23 	/**

    24 	 * Array of metadata queries.

    25 	 *

    26 	 * See WP_Meta_Query::__construct() for information on meta query arguments.

    27 	 *

    28 	 * @since 3.2.0

    29 	 * @var array

    30 	 */

    31 	public $queries = array();

    32 

    33 	/**

    34 	 * The relation between the queries. Can be one of 'AND' or 'OR'.

    35 	 *

    36 	 * @since 3.2.0

    37 	 * @var string

    38 	 */

    39 	public $relation;

    40 

    41 	/**

    42 	 * Database table to query for the metadata.

    43 	 *

    44 	 * @since 4.1.0

    45 	 * @var string

    46 	 */

    47 	public $meta_table;

    48 

    49 	/**

    50 	 * Column in meta_table that represents the ID of the object the metadata belongs to.

    51 	 *

    52 	 * @since 4.1.0

    53 	 * @var string

    54 	 */

    55 	public $meta_id_column;

    56 

    57 	/**

    58 	 * Database table that where the metadata's objects are stored (eg $wpdb->users).

    59 	 *

    60 	 * @since 4.1.0

    61 	 * @var string

    62 	 */

    63 	public $primary_table;

    64 

    65 	/**

    66 	 * Column in primary_table that represents the ID of the object.

    67 	 *

    68 	 * @since 4.1.0

    69 	 * @var string

    70 	 */

    71 	public $primary_id_column;

    72 

    73 	/**

    74 	 * A flat list of table aliases used in JOIN clauses.

    75 	 *

    76 	 * @since 4.1.0

    77 	 * @var array

    78 	 */

    79 	protected $table_aliases = array();

    80 

    81 	/**

    82 	 * A flat list of clauses, keyed by clause 'name'.

    83 	 *

    84 	 * @since 4.2.0

    85 	 * @var array

    86 	 */

    87 	protected $clauses = array();

    88 

    89 	/**

    90 	 * Whether the query contains any OR relations.

    91 	 *

    92 	 * @since 4.3.0

    93 	 * @var bool

    94 	 */

    95 	protected $has_or_relation = false;

    96 

    97 	/**

    98 	 * Constructor.

    99 	 *

   100 	 * @since 3.2.0

   101 	 * @since 4.2.0 Introduced support for naming query clauses by associative array keys.

   102 	 *

   103 	 *

   104 	 * @param array $meta_query {

   105 	 *     Array of meta query clauses. When first-order clauses or sub-clauses use strings as

   106 	 *     their array keys, they may be referenced in the 'orderby' parameter of the parent query.

   107 	 *

   108 	 *     @type string $relation Optional. The MySQL keyword used to join

   109 	 *                            the clauses of the query. Accepts 'AND', or 'OR'. Default 'AND'.

   110 	 *     @type array {

   111 	 *         Optional. An array of first-order clause parameters, or another fully-formed meta query.

   112 	 *

   113 	 *         @type string $key     Meta key to filter by.

   114 	 *         @type string $value   Meta value to filter by.

   115 	 *         @type string $compare MySQL operator used for comparing the $value. Accepts '=',

   116 	 *                               '!=', '>', '>=', '<', '<=', 'LIKE', 'NOT LIKE',

   117 	 *                               'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN', 'REGEXP',

   118 	 *                               'NOT REGEXP', 'RLIKE', 'EXISTS' or 'NOT EXISTS'.

   119 	 *                               Default is 'IN' when `$value` is an array, '=' otherwise.

   120 	 *         @type string $type    MySQL data type that the meta_value column will be CAST to for

   121 	 *                               comparisons. Accepts 'NUMERIC', 'BINARY', 'CHAR', 'DATE',

   122 	 *                               'DATETIME', 'DECIMAL', 'SIGNED', 'TIME', or 'UNSIGNED'.

   123 	 *                               Default is 'CHAR'.

   124 	 *     }

   125 	 * }

   126 	 */

   127 	public function __construct( $meta_query = false ) {

   128 		if ( !$meta_query )

   129 			return;

   130 

   131 		if ( isset( $meta_query['relation'] ) && strtoupper( $meta_query['relation'] ) == 'OR' ) {

   132 			$this->relation = 'OR';

   133 		} else {

   134 			$this->relation = 'AND';

   135 		}

   136 

   137 		$this->queries = $this->sanitize_query( $meta_query );

   138 	}

   139 

   140 	/**

   141 	 * Ensure the 'meta_query' argument passed to the class constructor is well-formed.

   142 	 *

   143 	 * Eliminates empty items and ensures that a 'relation' is set.

   144 	 *

   145 	 * @since 4.1.0

   146 	 *

   147 	 * @param array $queries Array of query clauses.

   148 	 * @return array Sanitized array of query clauses.

   149 	 */

   150 	public function sanitize_query( $queries ) {

   151 		$clean_queries = array();

   152 

   153 		if ( ! is_array( $queries ) ) {

   154 			return $clean_queries;

   155 		}

   156 

   157 		foreach ( $queries as $key => $query ) {

   158 			if ( 'relation' === $key ) {

   159 				$relation = $query;

   160 

   161 			} elseif ( ! is_array( $query ) ) {

   162 				continue;

   163 

   164 			// First-order clause.

   165 			} elseif ( $this->is_first_order_clause( $query ) ) {

   166 				if ( isset( $query['value'] ) && array() === $query['value'] ) {

   167 					unset( $query['value'] );

   168 				}

   169 

   170 				$clean_queries[ $key ] = $query;

   171 

   172 			// Otherwise, it's a nested query, so we recurse.

   173 			} else {

   174 				$cleaned_query = $this->sanitize_query( $query );

   175 

   176 				if ( ! empty( $cleaned_query ) ) {

   177 					$clean_queries[ $key ] = $cleaned_query;

   178 				}

   179 			}

   180 		}

   181 

   182 		if ( empty( $clean_queries ) ) {

   183 			return $clean_queries;

   184 		}

   185 

   186 		// Sanitize the 'relation' key provided in the query.

   187 		if ( isset( $relation ) && 'OR' === strtoupper( $relation ) ) {

   188 			$clean_queries['relation'] = 'OR';

   189 			$this->has_or_relation = true;

   190 

   191 		/*

   192 		 * If there is only a single clause, call the relation 'OR'.

   193 		 * This value will not actually be used to join clauses, but it

   194 		 * simplifies the logic around combining key-only queries.

   195 		 */

   196 		} elseif ( 1 === count( $clean_queries ) ) {

   197 			$clean_queries['relation'] = 'OR';

   198 

   199 		// Default to AND.

   200 		} else {

   201 			$clean_queries['relation'] = 'AND';

   202 		}

   203 

   204 		return $clean_queries;

   205 	}

   206 

   207 	/**

   208 	 * Determine whether a query clause is first-order.

   209 	 *

   210 	 * A first-order meta query clause is one that has either a 'key' or

   211 	 * a 'value' array key.

   212 	 *

   213 	 * @since 4.1.0

   214 	 *

   215 	 * @param array $query Meta query arguments.

   216 	 * @return bool Whether the query clause is a first-order clause.

   217 	 */

   218 	protected function is_first_order_clause( $query ) {

   219 		return isset( $query['key'] ) || isset( $query['value'] );

   220 	}

   221 

   222 	/**

   223 	 * Constructs a meta query based on 'meta_*' query vars

   224 	 *

   225 	 * @since 3.2.0

   226 	 *

   227 	 * @param array $qv The query variables

   228 	 */

   229 	public function parse_query_vars( $qv ) {

   230 		$meta_query = array();

   231 

   232 		/*

   233 		 * For orderby=meta_value to work correctly, simple query needs to be

   234 		 * first (so that its table join is against an unaliased meta table) and

   235 		 * needs to be its own clause (so it doesn't interfere with the logic of

   236 		 * the rest of the meta_query).

   237 		 */

   238 		$primary_meta_query = array();

   239 		foreach ( array( 'key', 'compare', 'type' ) as $key ) {

   240 			if ( ! empty( $qv[ "meta_$key" ] ) ) {

   241 				$primary_meta_query[ $key ] = $qv[ "meta_$key" ];

   242 			}

   243 		}

   244 

   245 		// WP_Query sets 'meta_value' = '' by default.

   246 		if ( isset( $qv['meta_value'] ) && '' !== $qv['meta_value'] && ( ! is_array( $qv['meta_value'] ) || $qv['meta_value'] ) ) {

   247 			$primary_meta_query['value'] = $qv['meta_value'];

   248 		}

   249 

   250 		$existing_meta_query = isset( $qv['meta_query'] ) && is_array( $qv['meta_query'] ) ? $qv['meta_query'] : array();

   251 

   252 		if ( ! empty( $primary_meta_query ) && ! empty( $existing_meta_query ) ) {

   253 			$meta_query = array(

   254 				'relation' => 'AND',

   255 				$primary_meta_query,

   256 				$existing_meta_query,

   257 			);

   258 		} elseif ( ! empty( $primary_meta_query ) ) {

   259 			$meta_query = array(

   260 				$primary_meta_query,

   261 			);

   262 		} elseif ( ! empty( $existing_meta_query ) ) {

   263 			$meta_query = $existing_meta_query;

   264 		}

   265 

   266 		$this->__construct( $meta_query );

   267 	}

   268 

   269 	/**

   270 	 * Return the appropriate alias for the given meta type if applicable.

   271 	 *

   272 	 * @since 3.7.0

   273 	 *

   274 	 * @param string $type MySQL type to cast meta_value.

   275 	 * @return string MySQL type.

   276 	 */

   277 	public function get_cast_for_type( $type = '' ) {

   278 		if ( empty( $type ) )

   279 			return 'CHAR';

   280 

   281 		$meta_type = strtoupper( $type );

   282 

   283 		if ( ! preg_match( '/^(?:BINARY|CHAR|DATE|DATETIME|SIGNED|UNSIGNED|TIME|NUMERIC(?:\(\d+(?:,\s?\d+)?\))?|DECIMAL(?:\(\d+(?:,\s?\d+)?\))?)$/', $meta_type ) )

   284 			return 'CHAR';

   285 

   286 		if ( 'NUMERIC' == $meta_type )

   287 			$meta_type = 'SIGNED';

   288 

   289 		return $meta_type;

   290 	}

   291 

   292 	/**

   293 	 * Generates SQL clauses to be appended to a main query.

   294 	 *

   295 	 * @since 3.2.0

   296 	 *

   297 	 * @param string $type              Type of meta, eg 'user', 'post'.

   298 	 * @param string $primary_table     Database table where the object being filtered is stored (eg wp_users).

   299 	 * @param string $primary_id_column ID column for the filtered object in $primary_table.

   300 	 * @param object $context           Optional. The main query object.

   301 	 * @return false|array {

   302 	 *     Array containing JOIN and WHERE SQL clauses to append to the main query.

   303 	 *

   304 	 *     @type string $join  SQL fragment to append to the main JOIN clause.

   305 	 *     @type string $where SQL fragment to append to the main WHERE clause.

   306 	 * }

   307 	 */

   308 	public function get_sql( $type, $primary_table, $primary_id_column, $context = null ) {

   309 		if ( ! $meta_table = _get_meta_table( $type ) ) {

   310 			return false;

   311 		}

   312 

   313 		$this->table_aliases = array();

   314 

   315 		$this->meta_table     = $meta_table;

   316 		$this->meta_id_column = sanitize_key( $type . '_id' );

   317 

   318 		$this->primary_table     = $primary_table;

   319 		$this->primary_id_column = $primary_id_column;

   320 

   321 		$sql = $this->get_sql_clauses();

   322 

   323 		/*

   324 		 * If any JOINs are LEFT JOINs (as in the case of NOT EXISTS), then all JOINs should

   325 		 * be LEFT. Otherwise posts with no metadata will be excluded from results.

   326 		 */

   327 		if ( false !== strpos( $sql['join'], 'LEFT JOIN' ) ) {

   328 			$sql['join'] = str_replace( 'INNER JOIN', 'LEFT JOIN', $sql['join'] );

   329 		}

   330 

   331 		/**

   332 		 * Filters the meta query's generated SQL.

   333 		 *

   334 		 * @since 3.1.0

   335 		 *

   336 		 * @param array  $clauses           Array containing the query's JOIN and WHERE clauses.

   337 		 * @param array  $queries           Array of meta queries.

   338 		 * @param string $type              Type of meta.

   339 		 * @param string $primary_table     Primary table.

   340 		 * @param string $primary_id_column Primary column ID.

   341 		 * @param object $context           The main query object.

   342 		 */

   343 		return apply_filters_ref_array( 'get_meta_sql', array( $sql, $this->queries, $type, $primary_table, $primary_id_column, $context ) );

   344 	}

   345 

   346 	/**

   347 	 * Generate SQL clauses to be appended to a main query.

   348 	 *

   349 	 * Called by the public WP_Meta_Query::get_sql(), this method is abstracted

   350 	 * out to maintain parity with the other Query classes.

   351 	 *

   352 	 * @since 4.1.0

   353 	 *

   354 	 * @return array {

   355 	 *     Array containing JOIN and WHERE SQL clauses to append to the main query.

   356 	 *

   357 	 *     @type string $join  SQL fragment to append to the main JOIN clause.

   358 	 *     @type string $where SQL fragment to append to the main WHERE clause.

   359 	 * }

   360 	 */

   361 	protected function get_sql_clauses() {

   362 		/*

   363 		 * $queries are passed by reference to get_sql_for_query() for recursion.

   364 		 * To keep $this->queries unaltered, pass a copy.

   365 		 */

   366 		$queries = $this->queries;

   367 		$sql = $this->get_sql_for_query( $queries );

   368 

   369 		if ( ! empty( $sql['where'] ) ) {

   370 			$sql['where'] = ' AND ' . $sql['where'];

   371 		}

   372 

   373 		return $sql;

   374 	}

   375 

   376 	/**

   377 	 * Generate SQL clauses for a single query array.

   378 	 *

   379 	 * If nested subqueries are found, this method recurses the tree to

   380 	 * produce the properly nested SQL.

   381 	 *

   382 	 * @since 4.1.0

   383 	 *

   384 	 * @param array $query Query to parse (passed by reference).

   385 	 * @param int   $depth Optional. Number of tree levels deep we currently are.

   386 	 *                     Used to calculate indentation. Default 0.

   387 	 * @return array {

   388 	 *     Array containing JOIN and WHERE SQL clauses to append to a single query array.

   389 	 *

   390 	 *     @type string $join  SQL fragment to append to the main JOIN clause.

   391 	 *     @type string $where SQL fragment to append to the main WHERE clause.

   392 	 * }

   393 	 */

   394 	protected function get_sql_for_query( &$query, $depth = 0 ) {

   395 		$sql_chunks = array(

   396 			'join'  => array(),

   397 			'where' => array(),

   398 		);

   399 

   400 		$sql = array(

   401 			'join'  => '',

   402 			'where' => '',

   403 		);

   404 

   405 		$indent = '';

   406 		for ( $i = 0; $i < $depth; $i++ ) {

   407 			$indent .= "  ";

   408 		}

   409 

   410 		foreach ( $query as $key => &$clause ) {

   411 			if ( 'relation' === $key ) {

   412 				$relation = $query['relation'];

   413 			} elseif ( is_array( $clause ) ) {

   414 

   415 				// This is a first-order clause.

   416 				if ( $this->is_first_order_clause( $clause ) ) {

   417 					$clause_sql = $this->get_sql_for_clause( $clause, $query, $key );

   418 

   419 					$where_count = count( $clause_sql['where'] );

   420 					if ( ! $where_count ) {

   421 						$sql_chunks['where'][] = '';

   422 					} elseif ( 1 === $where_count ) {

   423 						$sql_chunks['where'][] = $clause_sql['where'][0];

   424 					} else {

   425 						$sql_chunks['where'][] = '( ' . implode( ' AND ', $clause_sql['where'] ) . ' )';

   426 					}

   427 

   428 					$sql_chunks['join'] = array_merge( $sql_chunks['join'], $clause_sql['join'] );

   429 				// This is a subquery, so we recurse.

   430 				} else {

   431 					$clause_sql = $this->get_sql_for_query( $clause, $depth + 1 );

   432 

   433 					$sql_chunks['where'][] = $clause_sql['where'];

   434 					$sql_chunks['join'][]  = $clause_sql['join'];

   435 				}

   436 			}

   437 		}

   438 

   439 		// Filter to remove empties.

   440 		$sql_chunks['join']  = array_filter( $sql_chunks['join'] );

   441 		$sql_chunks['where'] = array_filter( $sql_chunks['where'] );

   442 

   443 		if ( empty( $relation ) ) {

   444 			$relation = 'AND';

   445 		}

   446 

   447 		// Filter duplicate JOIN clauses and combine into a single string.

   448 		if ( ! empty( $sql_chunks['join'] ) ) {

   449 			$sql['join'] = implode( ' ', array_unique( $sql_chunks['join'] ) );

   450 		}

   451 

   452 		// Generate a single WHERE clause with proper brackets and indentation.

   453 		if ( ! empty( $sql_chunks['where'] ) ) {

   454 			$sql['where'] = '( ' . "\n  " . $indent . implode( ' ' . "\n  " . $indent . $relation . ' ' . "\n  " . $indent, $sql_chunks['where'] ) . "\n" . $indent . ')';

   455 		}

   456 

   457 		return $sql;

   458 	}

   459 

   460 	/**

   461 	 * Generate SQL JOIN and WHERE clauses for a first-order query clause.

   462 	 *

   463 	 * "First-order" means that it's an array with a 'key' or 'value'.

   464 	 *

   465 	 * @since 4.1.0

   466 	 *

   467 	 * @global wpdb $wpdb WordPress database abstraction object.

   468 	 *

   469 	 * @param array  $clause       Query clause (passed by reference).

   470 	 * @param array  $parent_query Parent query array.

   471 	 * @param string $clause_key   Optional. The array key used to name the clause in the original `$meta_query`

   472 	 *                             parameters. If not provided, a key will be generated automatically.

   473 	 * @return array {

   474 	 *     Array containing JOIN and WHERE SQL clauses to append to a first-order query.

   475 	 *

   476 	 *     @type string $join  SQL fragment to append to the main JOIN clause.

   477 	 *     @type string $where SQL fragment to append to the main WHERE clause.

   478 	 * }

   479 	 */

   480 	public function get_sql_for_clause( &$clause, $parent_query, $clause_key = '' ) {

   481 		global $wpdb;

   482 

   483 		$sql_chunks = array(

   484 			'where' => array(),

   485 			'join' => array(),

   486 		);

   487 

   488 		if ( isset( $clause['compare'] ) ) {

   489 			$clause['compare'] = strtoupper( $clause['compare'] );

   490 		} else {

   491 			$clause['compare'] = isset( $clause['value'] ) && is_array( $clause['value'] ) ? 'IN' : '=';

   492 		}

   493 

   494 		if ( ! in_array( $clause['compare'], array(

   495 			'=', '!=', '>', '>=', '<', '<=',

   496 			'LIKE', 'NOT LIKE',

   497 			'IN', 'NOT IN',

   498 			'BETWEEN', 'NOT BETWEEN',

   499 			'EXISTS', 'NOT EXISTS',

   500 			'REGEXP', 'NOT REGEXP', 'RLIKE'

   501 		) ) ) {

   502 			$clause['compare'] = '=';

   503 		}

   504 

   505 		$meta_compare = $clause['compare'];

   506 

   507 		// First build the JOIN clause, if one is required.

   508 		$join = '';

   509 

   510 		// We prefer to avoid joins if possible. Look for an existing join compatible with this clause.

   511 		$alias = $this->find_compatible_table_alias( $clause, $parent_query );

   512 		if ( false === $alias ) {

   513 			$i = count( $this->table_aliases );

   514 			$alias = $i ? 'mt' . $i : $this->meta_table;

   515 

   516 			// JOIN clauses for NOT EXISTS have their own syntax.

   517 			if ( 'NOT EXISTS' === $meta_compare ) {

   518 				$join .= " LEFT JOIN $this->meta_table";

   519 				$join .= $i ? " AS $alias" : '';

   520 				$join .= $wpdb->prepare( " ON ($this->primary_table.$this->primary_id_column = $alias.$this->meta_id_column AND $alias.meta_key = %s )", $clause['key'] );

   521 

   522 			// All other JOIN clauses.

   523 			} else {

   524 				$join .= " INNER JOIN $this->meta_table";

   525 				$join .= $i ? " AS $alias" : '';

   526 				$join .= " ON ( $this->primary_table.$this->primary_id_column = $alias.$this->meta_id_column )";

   527 			}

   528 

   529 			$this->table_aliases[] = $alias;

   530 			$sql_chunks['join'][] = $join;

   531 		}

   532 

   533 		// Save the alias to this clause, for future siblings to find.

   534 		$clause['alias'] = $alias;

   535 

   536 		// Determine the data type.

   537 		$_meta_type = isset( $clause['type'] ) ? $clause['type'] : '';

   538 		$meta_type  = $this->get_cast_for_type( $_meta_type );

   539 		$clause['cast'] = $meta_type;

   540 

   541 		// Fallback for clause keys is the table alias. Key must be a string.

   542 		if ( is_int( $clause_key ) || ! $clause_key ) {

   543 			$clause_key = $clause['alias'];

   544 		}

   545 

   546 		// Ensure unique clause keys, so none are overwritten.

   547 		$iterator = 1;

   548 		$clause_key_base = $clause_key;

   549 		while ( isset( $this->clauses[ $clause_key ] ) ) {

   550 			$clause_key = $clause_key_base . '-' . $iterator;

   551 			$iterator++;

   552 		}

   553 

   554 		// Store the clause in our flat array.

   555 		$this->clauses[ $clause_key ] =& $clause;

   556 

   557 		// Next, build the WHERE clause.

   558 

   559 		// meta_key.

   560 		if ( array_key_exists( 'key', $clause ) ) {

   561 			if ( 'NOT EXISTS' === $meta_compare ) {

   562 				$sql_chunks['where'][] = $alias . '.' . $this->meta_id_column . ' IS NULL';

   563 			} else {

   564 				$sql_chunks['where'][] = $wpdb->prepare( "$alias.meta_key = %s", trim( $clause['key'] ) );

   565 			}

   566 		}

   567 

   568 		// meta_value.

   569 		if ( array_key_exists( 'value', $clause ) ) {

   570 			$meta_value = $clause['value'];

   571 

   572 			if ( in_array( $meta_compare, array( 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ) ) ) {

   573 				if ( ! is_array( $meta_value ) ) {

   574 					$meta_value = preg_split( '/[,\s]+/', $meta_value );

   575 				}

   576 			} else {

   577 				$meta_value = trim( $meta_value );

   578 			}

   579 

   580 			switch ( $meta_compare ) {

   581 				case 'IN' :

   582 				case 'NOT IN' :

   583 					$meta_compare_string = '(' . substr( str_repeat( ',%s', count( $meta_value ) ), 1 ) . ')';

   584 					$where = $wpdb->prepare( $meta_compare_string, $meta_value );

   585 					break;

   586 

   587 				case 'BETWEEN' :

   588 				case 'NOT BETWEEN' :

   589 					$meta_value = array_slice( $meta_value, 0, 2 );

   590 					$where = $wpdb->prepare( '%s AND %s', $meta_value );

   591 					break;

   592 

   593 				case 'LIKE' :

   594 				case 'NOT LIKE' :

   595 					$meta_value = '%' . $wpdb->esc_like( $meta_value ) . '%';

   596 					$where = $wpdb->prepare( '%s', $meta_value );

   597 					break;

   598 

   599 				// EXISTS with a value is interpreted as '='.

   600 				case 'EXISTS' :

   601 					$meta_compare = '=';

   602 					$where = $wpdb->prepare( '%s', $meta_value );

   603 					break;

   604 

   605 				// 'value' is ignored for NOT EXISTS.

   606 				case 'NOT EXISTS' :

   607 					$where = '';

   608 					break;

   609 

   610 				default :

   611 					$where = $wpdb->prepare( '%s', $meta_value );

   612 					break;

   613 

   614 			}

   615 

   616 			if ( $where ) {

   617 				if ( 'CHAR' === $meta_type ) {

   618 					$sql_chunks['where'][] = "$alias.meta_value {$meta_compare} {$where}";

   619 				} else {

   620 					$sql_chunks['where'][] = "CAST($alias.meta_value AS {$meta_type}) {$meta_compare} {$where}";

   621 				}

   622 			}

   623 		}

   624 

   625 		/*

   626 		 * Multiple WHERE clauses (for meta_key and meta_value) should

   627 		 * be joined in parentheses.

   628 		 */

   629 		if ( 1 < count( $sql_chunks['where'] ) ) {

   630 			$sql_chunks['where'] = array( '( ' . implode( ' AND ', $sql_chunks['where'] ) . ' )' );

   631 		}

   632 

   633 		return $sql_chunks;

   634 	}

   635 

   636 	/**

   637 	 * Get a flattened list of sanitized meta clauses.

   638 	 *

   639 	 * This array should be used for clause lookup, as when the table alias and CAST type must be determined for

   640 	 * a value of 'orderby' corresponding to a meta clause.

   641 	 *

   642 	 * @since 4.2.0

   643 	 *

   644 	 * @return array Meta clauses.

   645 	 */

   646 	public function get_clauses() {

   647 		return $this->clauses;

   648 	}

   649 

   650 	/**

   651 	 * Identify an existing table alias that is compatible with the current

   652 	 * query clause.

   653 	 *

   654 	 * We avoid unnecessary table joins by allowing each clause to look for

   655 	 * an existing table alias that is compatible with the query that it

   656 	 * needs to perform.

   657 	 *

   658 	 * An existing alias is compatible if (a) it is a sibling of `$clause`

   659 	 * (ie, it's under the scope of the same relation), and (b) the combination

   660 	 * of operator and relation between the clauses allows for a shared table join.

   661 	 * In the case of WP_Meta_Query, this only applies to 'IN' clauses that are

   662 	 * connected by the relation 'OR'.

   663 	 *

   664 	 * @since 4.1.0

   665 	 *

   666 	 * @param  array       $clause       Query clause.

   667 	 * @param  array       $parent_query Parent query of $clause.

   668 	 * @return string|bool Table alias if found, otherwise false.

   669 	 */

   670 	protected function find_compatible_table_alias( $clause, $parent_query ) {

   671 		$alias = false;

   672 

   673 		foreach ( $parent_query as $sibling ) {

   674 			// If the sibling has no alias yet, there's nothing to check.

   675 			if ( empty( $sibling['alias'] ) ) {

   676 				continue;

   677 			}

   678 

   679 			// We're only interested in siblings that are first-order clauses.

   680 			if ( ! is_array( $sibling ) || ! $this->is_first_order_clause( $sibling ) ) {

   681 				continue;

   682 			}

   683 

   684 			$compatible_compares = array();

   685 

   686 			// Clauses connected by OR can share joins as long as they have "positive" operators.

   687 			if ( 'OR' === $parent_query['relation'] ) {

   688 				$compatible_compares = array( '=', 'IN', 'BETWEEN', 'LIKE', 'REGEXP', 'RLIKE', '>', '>=', '<', '<=' );

   689 

   690 			// Clauses joined by AND with "negative" operators share a join only if they also share a key.

   691 			} elseif ( isset( $sibling['key'] ) && isset( $clause['key'] ) && $sibling['key'] === $clause['key'] ) {

   692 				$compatible_compares = array( '!=', 'NOT IN', 'NOT LIKE' );

   693 			}

   694 

   695 			$clause_compare  = strtoupper( $clause['compare'] );

   696 			$sibling_compare = strtoupper( $sibling['compare'] );

   697 			if ( in_array( $clause_compare, $compatible_compares ) && in_array( $sibling_compare, $compatible_compares ) ) {

   698 				$alias = $sibling['alias'];

   699 				break;

   700 			}

   701 		}

   702 

   703 		/**

   704 		 * Filters the table alias identified as compatible with the current clause.

   705 		 *

   706 		 * @since 4.1.0

   707 		 *

   708 		 * @param string|bool $alias        Table alias, or false if none was found.

   709 		 * @param array       $clause       First-order query clause.

   710 		 * @param array       $parent_query Parent of $clause.

   711 		 * @param object      $this         WP_Meta_Query object.

   712 		 */

   713 		return apply_filters( 'meta_query_find_compatible_table_alias', $alias, $clause, $parent_query, $this ) ;

   714 	}

   715 

   716 	/**

   717 	 * Checks whether the current query has any OR relations.

   718 	 *

   719 	 * In some cases, the presence of an OR relation somewhere in the query will require

   720 	 * the use of a `DISTINCT` or `GROUP BY` keyword in the `SELECT` clause. The current

   721 	 * method can be used in these cases to determine whether such a clause is necessary.

   722 	 *

   723 	 * @since 4.3.0

   724 	 *

   725 	 * @return bool True if the query contains any `OR` relations, otherwise false.

   726 	 */

   727 	public function has_or_relation() {

   728 		return $this->has_or_relation;

   729 	}

   730 }