130 lines
4.3 KiB
PHP
130 lines
4.3 KiB
PHP
<?php
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namespace SilverStripe\MSSQL;
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use InvalidArgumentException;
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use SilverStripe\ORM\Queries\SQLSelect;
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use SilverStripe\ORM\Connect\DBQueryBuilder;
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/**
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* Builds a SQL query string from a SQLExpression object
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*
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* @package mssql
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*/
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class MSSQLQueryBuilder extends DBQueryBuilder
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{
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protected function buildSelectQuery(SQLSelect $query, array &$parameters)
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{
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list($limit, $offset) = $this->parseLimit($query);
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// If not using ofset then query generation is quite straightforward
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if (empty($offset)) {
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$sql = parent::buildSelectQuery($query, $parameters);
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// Inject limit into SELECT fragment
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if (!empty($limit)) {
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$sql = preg_replace('/^(SELECT (DISTINCT)?)/i', '${1} TOP '.$limit, $sql);
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}
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return $sql;
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}
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// When using offset we must use a subselect
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// @see http://stackoverflow.com/questions/2135418/equivalent-of-limit-and-offset-for-sql-server
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$orderby = $query->getOrderBy();
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// workaround for subselect not working with alias functions
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// just use the function directly in the order by instead of the alias
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$selects = $query->getSelect();
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foreach ($orderby as $field => $dir) {
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if (preg_match('/_SortColumn/', $field)) {
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unset($orderby[$field]);
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$orderby[$selects[str_replace('"', '', $field)]] = $dir;
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}
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}
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// Create order expression, using the first column if none explicitly specified
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if ($orderby) {
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// Simple implementation of buildOrderByFragment
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$statements = array();
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foreach ($orderby as $clause => $dir) {
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$statements[] = trim("$clause $dir");
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}
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$orderByClause = "ORDER BY " . implode(', ', $statements);
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} else {
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$selects = $query->getSelect();
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$firstCol = reset($selects);
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$orderByClause = "ORDER BY $firstCol";
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}
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// Build main query SQL
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$sql = parent::buildSelectQuery($query, $parameters);
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// Inject row number into selection
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$sql = preg_replace('/^(SELECT (DISTINCT)?)/i', '${1} ROW_NUMBER() OVER ('.$orderByClause.') AS Number, ', $sql);
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// Sub-query this SQL
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if (empty($limit)) {
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$limitCondition = "Number > ?";
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$parameters[] = $offset;
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} else {
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$limitCondition = "Number BETWEEN ? AND ?";
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$parameters[] = $offset + 1;
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$parameters[] = $offset + $limit;
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}
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return "SELECT * FROM ($sql) AS Numbered WHERE $limitCondition ORDER BY Number";
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}
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public function buildLimitFragment(SQLSelect $query, array &$parameters)
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{
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// Limit is handled at the buildSelectQuery level
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return '';
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}
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public function buildOrderByFragment(SQLSelect $query, array &$parameters)
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{
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// If doing a limit/offset at the same time then don't build the orde by fragment here
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list($offset, $limit) = $this->parseLimit($query);
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if (empty($offset) || empty($limit)) {
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return parent::buildOrderByFragment($query, $parameters);
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}
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return '';
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}
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/**
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* Extracts the limit and offset from the limit clause
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*
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* @param SQLSelect $query
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* @return array Two item array with $limit and $offset as values
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* @throws InvalidArgumentException
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*/
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protected function parseLimit(SQLSelect $query)
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{
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$limit = '';
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$offset = '0';
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if (is_array($query->getLimit())) {
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$limitArr = $query->getLimit();
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if (isset($limitArr['limit'])) {
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$limit = $limitArr['limit'];
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}
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if (isset($limitArr['start'])) {
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$offset = $limitArr['start'];
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}
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} elseif (preg_match('/^([0-9]+) offset ([0-9]+)$/i', trim($query->getLimit()), $matches)) {
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$limit = $matches[1];
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$offset = $matches[2];
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} else {
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//could be a comma delimited string
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$bits = explode(',', $query->getLimit());
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if (sizeof($bits) > 1) {
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list($offset, $limit) = $bits;
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} else {
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$limit = $bits[0];
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}
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}
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return array($limit, $offset);
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}
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}
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