connection = $resource->getConnection(); } /** * Wrap query with parentheses. * * @param string $query * @return string */ public function wrapBrackets($query) { return empty($query) ? $query : '(' . $query . ')'; } /** * Combine multiple queries. * * @param string[] $queries * @param string $unionOperator * @return string */ public function combineQueries(array $queries, $unionOperator) { return implode( ' ' . $unionOperator . ' ', array_filter($queries, 'strlen') ); } /** * Generate query condition. * * @param string $field * @param string $operator * @param mixed $value * @return string */ public function generateCondition($field, $operator, $value) { return sprintf( is_array($value) ? self::CONDITION_PATTERN_ARRAY : self::CONDITION_PATTERN_SIMPLE, $this->connection->quoteIdentifier($field), $operator, $this->connection->quote($value) ); } }