Doctrine\DBAL\Platforms\SQLServerPlatform::doModifyLimitQuery()

Complexity

Conditions	5
Paths	12

Size

Total Lines	42
Code Lines	23

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	17
CRAP Score	5.0291

Importance

Changes

0

<?php
    protected function doModifyLimitQuery($query, $limit, $offset = null)
    {
        $where = [];

        if ($offset > 0) {
            $where[] = sprintf('doctrine_rownum >= %d', $offset + 1);
        }

        if ($limit !== null) {
            $where[] = sprintf('doctrine_rownum <= %d', $offset + $limit);
            $top     = sprintf('TOP %d', $offset + $limit);
        } else {
            $top = 'TOP 9223372036854775807';
        }

        if (empty($where)) {
            return $query;
        }

        // We'll find a SELECT or SELECT distinct and prepend TOP n to it
        // Even if the TOP n is very large, the use of a CTE will
        // allow the SQL Server query planner to optimize it so it doesn't
        // actually scan the entire range covered by the TOP clause.
        $selectPattern = '/^(\s*SELECT\s+(?:DISTINCT\s+)?)(.*)$/im';
        $replacePattern = sprintf('$1%s $2', $top);
        $query = preg_replace($selectPattern, $replacePattern, $query);

        if (stristr($query, "ORDER BY")) {
            // Inner order by is not valid in SQL Server for our purposes
            // unless it's in a TOP N subquery.
            $query = $this->scrubInnerOrderBy($query);
        }

        // Build a new limited query around the original, using a CTE
        return sprintf(
            "WITH dctrn_cte AS (%s) "
            . "SELECT * FROM ("
            . "SELECT *, ROW_NUMBER() OVER (ORDER BY (SELECT 0)) AS doctrine_rownum FROM dctrn_cte"
            . ") AS doctrine_tbl "
            . 'WHERE %s ORDER BY doctrine_rownum ASC',
            $query,
            implode(' AND ', $where)
        );