wp-includes/class-wpdb.php:3304Retrieves the character set for the given column.
$tablestring$columnstringstring|false|WP_ErrorOne hook fires while wpdb::get_col_charset() runs, in this order:
Filters the column charset value before the DB is checked.
public function get_col_charset( $table, $column ) { $tablekey = strtolower( $table ); $columnkey = strtolower( $column ); /** * Filters the column charset value before the DB is checked. * * Passing a non-null value to the filter will short-circuit * checking the DB for the charset, returning that value instead. * * @since 4.2.0 * * @param string|null|false|WP_Error $charset The character set to use. Default null. * @param string $table The name of the table being checked. * @param string $column The name of the column being checked. */ $charset = apply_filters( 'pre_get_col_charset', null, $table, $column ); if ( null !== $charset ) { return $charset; } // Skip this entirely if this isn't a MySQL database. if ( empty( $this->is_mysql ) ) { return false; } if ( empty( $this->table_charset[ $tablekey ] ) ) { // This primes column information for us. $table_charset = $this->get_table_charset( $table ); if ( is_wp_error( $table_charset ) ) { return $table_charset; } } // If still no column information, return the table charset. if ( empty( $this->col_meta[ $tablekey ] ) ) { return $this->table_charset[ $tablekey ]; } // If this column doesn't exist, return the table charset. if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) { return $this->table_charset[ $tablekey ]; } // Return false when it's not a string column. if ( empty( $this->col_meta[ $tablekey ][ $columnkey ]->Collation ) ) { return false; } list( $charset ) = explode( '_', $this->col_meta[ $tablekey ][ $columnkey ]->Collation ); return $charset; }Introduced in 4.2.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wpdb.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.