}
# Split database and table into proper variables.
- # We reverse the explode so that database.table and table both output
- # the correct table.
+ list( $database, $schema, $prefix, $table ) = $this->qualifiedTableComponents( $name );
+
+ # Quote $table and apply the prefix if not quoted.
+ # $tableName might be empty if this is called from Database::replaceVars()
+ $tableName = "{$prefix}{$table}";
+ if ( $format === 'quoted'
+ && !$this->isQuotedIdentifier( $tableName )
+ && $tableName !== ''
+ ) {
+ $tableName = $this->addIdentifierQuotes( $tableName );
+ }
+
+ # Quote $schema and $database and merge them with the table name if needed
+ $tableName = $this->prependDatabaseOrSchema( $schema, $tableName, $format );
+ $tableName = $this->prependDatabaseOrSchema( $database, $tableName, $format );
+
+ return $tableName;
+ }
+
+ /**
+ * Get the table components needed for a query given the currently selected database
+ *
+ * @param string $name Table name in the form of db.schema.table, db.table, or table
+ * @return array (DB name or "" for default, schema name, table prefix, table name)
+ */
+ protected function qualifiedTableComponents( $name ) {
+ # We reverse the explode so that database.table and table both output the correct table.
$dbDetails = explode( '.', $name, 3 );
if ( count( $dbDetails ) == 3 ) {
list( $database, $schema, $table ) = $dbDetails;
}
}
- # Quote $table and apply the prefix if not quoted.
- # $tableName might be empty if this is called from Database::replaceVars()
- $tableName = "{$prefix}{$table}";
- if ( $format === 'quoted'
- && !$this->isQuotedIdentifier( $tableName )
- && $tableName !== ''
- ) {
- $tableName = $this->addIdentifierQuotes( $tableName );
- }
-
- # Quote $schema and $database and merge them with the table name if needed
- $tableName = $this->prependDatabaseOrSchema( $schema, $tableName, $format );
- $tableName = $this->prependDatabaseOrSchema( $database, $tableName, $format );
-
- return $tableName;
+ return [ $database, $schema, $prefix, $table ];
}
/**
return '(' . implode( $glue, $sqls ) . ')';
}
+ public function unionConditionPermutations(
+ $table, $vars, array $permute_conds, $extra_conds = '', $fname = __METHOD__,
+ $options = [], $join_conds = []
+ ) {
+ // First, build the Cartesian product of $permute_conds
+ $conds = [ [] ];
+ foreach ( $permute_conds as $field => $values ) {
+ if ( !$values ) {
+ // Skip empty $values
+ continue;
+ }
+ $values = array_unique( $values ); // For sanity
+ $newConds = [];
+ foreach ( $conds as $cond ) {
+ foreach ( $values as $value ) {
+ $cond[$field] = $value;
+ $newConds[] = $cond; // Arrays are by-value, not by-reference, so this works
+ }
+ }
+ $conds = $newConds;
+ }
+
+ $extra_conds = $extra_conds === '' ? [] : (array)$extra_conds;
+
+ // If there's just one condition and no subordering, hand off to
+ // selectSQLText directly.
+ if ( count( $conds ) === 1 &&
+ ( !isset( $options['INNER ORDER BY'] ) || !$this->unionSupportsOrderAndLimit() )
+ ) {
+ return $this->selectSQLText(
+ $table, $vars, $conds[0] + $extra_conds, $fname, $options, $join_conds
+ );
+ }
+
+ // Otherwise, we need to pull out the order and limit to apply after
+ // the union. Then build the SQL queries for each set of conditions in
+ // $conds. Then union them together (using UNION ALL, because the
+ // product *should* already be distinct).
+ $orderBy = $this->makeOrderBy( $options );
+ $limit = isset( $options['LIMIT'] ) ? $options['LIMIT'] : null;
+ $offset = isset( $options['OFFSET'] ) ? $options['OFFSET'] : false;
+ $all = empty( $options['NOTALL'] ) && !in_array( 'NOTALL', $options );
+ if ( !$this->unionSupportsOrderAndLimit() ) {
+ unset( $options['ORDER BY'], $options['LIMIT'], $options['OFFSET'] );
+ } else {
+ if ( array_key_exists( 'INNER ORDER BY', $options ) ) {
+ $options['ORDER BY'] = $options['INNER ORDER BY'];
+ }
+ if ( $limit !== null && is_numeric( $offset ) && $offset != 0 ) {
+ // We need to increase the limit by the offset rather than
+ // using the offset directly, otherwise it'll skip incorrectly
+ // in the subqueries.
+ $options['LIMIT'] = $limit + $offset;
+ unset( $options['OFFSET'] );
+ }
+ }
+
+ $sqls = [];
+ foreach ( $conds as $cond ) {
+ $sqls[] = $this->selectSQLText(
+ $table, $vars, $cond + $extra_conds, $fname, $options, $join_conds
+ );
+ }
+ $sql = $this->unionQueries( $sqls, $all ) . $orderBy;
+ if ( $limit !== null ) {
+ $sql = $this->limitResult( $sql, $limit, $offset );
+ }
+
+ return $sql;
+ }
+
public function conditional( $cond, $trueVal, $falseVal ) {
if ( is_array( $cond ) ) {
$cond = $this->makeList( $cond, self::LIST_AND );
* @param array $selectJoinConds Join conditions for the SELECT part of the query, see
* IDatabase::select() for details.
*
- * @return IResultWrapper
+ * @return bool
*/
public function insertSelect( $destTable, $srcTable, $varMap, $conds,
$fname = __METHOD__,
*/
public function unionQueries( $sqls, $all );
+ /**
+ * Construct a UNION query for permutations of conditions
+ *
+ * Databases sometimes have trouble with queries that have multiple values
+ * for multiple condition parameters combined with limits and ordering.
+ * This method constructs queries for the Cartesian product of the
+ * conditions and unions them all together.
+ *
+ * @see IDatabase::select()
+ * @since 1.30
+ * @param string|array $table Table name
+ * @param string|array $vars Field names
+ * @param array $permute_conds Conditions for the Cartesian product. Keys
+ * are field names, values are arrays of the possible values for that
+ * field.
+ * @param string|array $extra_conds Additional conditions to include in the
+ * query.
+ * @param string $fname Caller function name
+ * @param string|array $options Query options. In addition to the options
+ * recognized by IDatabase::select(), the following may be used:
+ * - NOTALL: Set to use UNION instead of UNION ALL.
+ * - INNER ORDER BY: If specified and supported, subqueries will use this
+ * instead of ORDER BY.
+ * @param string|array $join_conds Join conditions
+ * @return string SQL query string.
+ */
+ public function unionConditionPermutations(
+ $table, $vars, array $permute_conds, $extra_conds = '', $fname = __METHOD__,
+ $options = [], $join_conds = []
+ );
+
/**
* Returns an SQL expression for a simple conditional. This doesn't need
* to be overridden unless CASE isn't supported in your DBMS.