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WP_Tax_Query::get_sql_for_clause( array $clause, array $parent_query ): array

Since
4.1.0
Source
wp-includes/class-wp-tax-query.php:384
Generates SQL JOIN and WHERE clauses for a "first-order" query clause.

Compatibility

WordPress
since 4.1.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$clausearray
Query clause (passed by reference).
$parent_queryarray
Parent query array.

Return value

array
Array containing JOIN and WHERE SQL clauses to append to a first-order query.
  • $joinstring[]

    Array of SQL fragments to append to the main JOIN clause.
  • $wherestring[]

    Array of SQL fragments to append to the main WHERE clause.

Performance profile

How much work a call to WP_Tax_Query::get_sql_for_clause() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Trivial

Touches nothing outside its own arguments.

Scaling
Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions
15–75

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 161.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
1

1 place in core call this, so the cost is paid more often than your own code shows.

What it touches

  • hookthird-party callbacksdo_action()one call below WP_Tax_Query::get_sql_for_clause()

What one call costs · 4 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost WP_Tax_Query::get_sql_for_clause() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
is_wp_error()15->clean_query(), is_wp_error()
!is_wp_error()25–52->clean_query(), is_wp_error(), strtoupper()
!is_wp_error() && $operator === "IN" && !empty($terms)47–75->clean_query(), is_wp_error(), strtoupper(), ->find_compatible_table_alias()
!is_wp_error() && $operator !== "IN" && $operator !== "NOT IN" && $operator !== "AND"67–69->clean_query(), is_wp_error(), strtoupper(), ->prepare()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev16115–7512
8.516115–7512
8.416115–75129 fewer instructions than PHP 8.3
8.317015–7812
8.217015–7812
8.117015–78123 fewer instructions than PHP 7.4
7.417315–8012

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 3

Used by · 1

Source code

	public function get_sql_for_clause( &$clause, $parent_query ) {		global $wpdb; 		$sql = array(			'where' => array(),			'join'  => array(),		); 		$join  = '';		$where = ''; 		$this->clean_query( $clause ); 		if ( is_wp_error( $clause ) ) {			return self::$no_results;		} 		$terms    = $clause['terms'];		$operator = strtoupper( $clause['operator'] ); 		if ( 'IN' === $operator ) { 			if ( empty( $terms ) ) {				return self::$no_results;			} 			$terms = implode( ',', $terms ); 			/*			 * Before creating another table join, see if this clause has a			 * sibling with an existing join that can be shared.			 */			$alias = $this->find_compatible_table_alias( $clause, $parent_query );			if ( false === $alias ) {				$i     = count( $this->table_aliases );				$alias = $i ? 'tt' . $i : $wpdb->term_relationships; 				// Store the alias as part of a flat array to build future iterators.				$this->table_aliases[] = $alias; 				// Store the alias with this clause, so later siblings can use it.				$clause['alias'] = $alias; 				$join .= " LEFT JOIN $wpdb->term_relationships";				$join .= $i ? " AS $alias" : '';				$join .= " ON ($this->primary_table.$this->primary_id_column = $alias.object_id)";			} 			$where = "$alias.term_taxonomy_id $operator ($terms)"; 		} elseif ( 'NOT IN' === $operator ) { 			if ( empty( $terms ) ) {				return $sql;			} 			$terms = implode( ',', $terms ); 			$where = "$this->primary_table.$this->primary_id_column NOT IN (				SELECT object_id				FROM $wpdb->term_relationships				WHERE term_taxonomy_id IN ($terms)			)"; 		} elseif ( 'AND' === $operator ) { 			if ( empty( $terms ) ) {				return $sql;			} 			$num_terms = count( $terms ); 			$terms = implode( ',', $terms ); 			$where = "(				SELECT COUNT(1)				FROM $wpdb->term_relationships				WHERE term_taxonomy_id IN ($terms)				AND object_id = $this->primary_table.$this->primary_id_column			) = $num_terms";

Changelog

Introduced in 4.1.0. Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/class-wp-tax-query.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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