wpdb::prepare( string $query, array|mixed $args ): string|void

Description

$wpdb->prepare(
 "SELECT * FROM table WHERE column = %s AND field = %d OR other_field LIKE %s",
 array( 'foo', 1337, '%bar' )
);

$wpdb->prepare(
 "SELECT DATE_FORMAT(field, '%%c') FROM table WHERE column = %s",
 'foo'
);

$wpdb->prepare(
 "SELECT * FROM %i WHERE %i = %s",
 $table,
 $field,
 $value
);

Compatibility

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

Parameters

$querystring

Query statement with sprintf()-like placeholders.

$argsarray|mixed

The array of variables to substitute into the query's placeholders if being called with an array of arguments, or the first variable to substitute into the query's placeholders if being called with individual arguments.

Return value

string|void

Sanitized query string, if there is a query to prepare.

Performance profile

How much work a call to wpdb::prepare() 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

Light

Touches nothing outside its own arguments.

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

5–116

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 337.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

5

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

What it touches

• regexregular expression over the whole inputpreg_split()called directly
• hookthird-party callbacksdo_action()one call below wpdb::prepare()

Further down the call graph this can also reach query, option, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 9 distinct outcomes

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

Uses · 6

• wp_load_translations_early()Attempts an early load of translations.
• _doing_it_wrong()Marks something as being incorrectly called.
• __()Retrieves the translation of $text.
• wpdb::_escape_identifier_value()Escapes an identifier value without adding the surrounding quotes.
• wpdb::_real_escape()Real escape using mysqli_real_escape_string().
• wpdb::add_placeholder_escape()Adds a placeholder escape string, to escape anything that resembles a printf() placeholder.

Used by · 5

• wpdb::_insert_replace_helper()Helper function for insert and replace.
• wpdb::delete()Deletes a row in the table.
• wpdb::set_charset()Sets the connection's character set.
• wpdb::strip_invalid_text()Strips any invalid characters based on value/charset pairs.
• wpdb::update()Updates a row in the table.

Source code

View on Trac ↗View on GitHub ↗

1464	public function prepare( $query, ...$args ) {1465		if ( is_null( $query ) ) {1466			return;1467		}1468 1469		/*1470		 * This is not meant to be foolproof -- but it will catch obviously incorrect usage.1471		 *1472		 * Note: str_contains() is not used here, as this file can be included1473		 * directly outside of WordPress core, e.g. by HyperDB, in which case1474		 * the polyfills from wp-includes/compat.php are not loaded.1475		 */1476		if ( false === strpos( $query, '%' ) ) {1477			wp_load_translations_early();1478			_doing_it_wrong(1479				'wpdb::prepare',1480				sprintf(1481					/* translators: %s: wpdb::prepare() */1482					__( 'The query argument of %s must have a placeholder.' ),1483					'wpdb::prepare()'1484				),1485				'3.9.0'1486			);1487		}1488 1489		/*1490		 * Specify the formatting allowed in a placeholder. The following are allowed:1491		 *1492		 * - Sign specifier, e.g. $+d1493		 * - Numbered placeholders, e.g. %1$s1494		 * - Padding specifier, including custom padding characters, e.g. %05s, %'#5s1495		 * - Alignment specifier, e.g. %05-s1496		 * - Precision specifier, e.g. %.2f1497		 */1498		$allowed_format = '(?:[1-9][0-9]*[$])?[-+0-9]*(?: |0|\'.)?[-+0-9]*(?:\.[0-9]+)?';1499 1500		/*1501		 * If a %s placeholder already has quotes around it, removing the existing quotes1502		 * and re-inserting them ensures the quotes are consistent.1503		 *1504		 * For backward compatibility, this is only applied to %s, and not to placeholders like %1$s,1505		 * which are frequently used in the middle of longer strings, or as table name placeholders.1506		 */1507		$query = str_replace( "'%s'", '%s', $query ); // Strip any existing single quotes.1508		$query = str_replace( '"%s"', '%s', $query ); // Strip any existing double quotes.1509 1510		// Escape any unescaped percents (i.e. anything unrecognised).1511		$query = preg_replace( "/%(?:%|$|(?!($allowed_format)?[sdfFi]))/", '%%\\1', $query );1512 1513		// Extract placeholders from the query.1514		$split_query = preg_split( "/(^|[^%]|(?:%%)+)(%(?:$allowed_format)?[sdfFi])/", $query, -1, PREG_SPLIT_DELIM_CAPTURE );1515 1516		$split_query_count = count( $split_query );1517 1518		/*1519		 * Split always returns with 1 value before the first placeholder (even with $query = "%s"),1520		 * then 3 additional values per placeholder.1521		 */1522		$placeholder_count = ( ( $split_query_count - 1 ) / 3 );1523 1524		// If args were passed as an array, as in vsprintf(), move them up.1525		$passed_as_array = ( isset( $args[0] ) && is_array( $args[0] ) && 1 === count( $args ) );1526		if ( $passed_as_array ) {1527			$args = $args[0];1528		}1529 1530		$new_query       = '';1531		$key             = 2; // Keys 0 and 1 in $split_query contain values before the first placeholder.1532		$arg_id          = 0;1533		$arg_identifiers = array();1534		$arg_strings     = array();1535 1536		while ( $key < $split_query_count ) {1537			$placeholder = $split_query[ $key ];1538 1539			$format = substr( $placeholder, 1, -1 );1540			$type   = substr( $placeholder, -1 );1541 1542			if ( 'f' === $type && true === $this->allow_unsafe_unquoted_parameters1543				/*

Changelog

Introduced in 2.3.0. One change between 6.7.7 and 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 6.9.7 tag, from src/wp-includes/class-wpdb.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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