Query Builder for Yii 2.0 and SQL Server 2005, 2008 (without Limt/Offset support)

QueryBuilder.php

<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\db\mssql;

use yii\base\InvalidParamException;

/**
 * QueryBuilder is the query builder for MS SQL Server databases (version 2008 and above).
 *
 * @author Timur Ruziev <resurtm@gmail.com>
 * @since 2.0
 */
class QueryBuilder extends \yii\db\QueryBuilder
{
    /**
     * @var array mapping from abstract column types (keys) to physical column types (values).
     */
    public $typeMap = [
        Schema::TYPE_PK => 'int IDENTITY PRIMARY KEY',
        Schema::TYPE_BIGPK => 'bigint IDENTITY PRIMARY KEY',
        Schema::TYPE_STRING => 'varchar(255)',
        Schema::TYPE_TEXT => 'text',
        Schema::TYPE_SMALLINT => 'smallint',
        Schema::TYPE_INTEGER => 'int',
        Schema::TYPE_BIGINT => 'bigint',
        Schema::TYPE_FLOAT => 'float',
        Schema::TYPE_DECIMAL => 'decimal',
        Schema::TYPE_DATETIME => 'datetime',
        Schema::TYPE_TIMESTAMP => 'timestamp',
        Schema::TYPE_TIME => 'time',
        Schema::TYPE_DATE => 'date',
        Schema::TYPE_BINARY => 'binary',
        Schema::TYPE_BOOLEAN => 'bit',
        Schema::TYPE_MONEY => 'decimal(19,4)',
    ];

//	public function update($table, $columns, $condition, &$params)
//	{
//		return '';
//	}

//	public function delete($table, $condition, &$params)
//	{
//		return '';
//	}

    /**
     * @param integer $limit
     * @param integer $offset
     * @return string the LIMIT and OFFSET clauses built from [[\yii\db\Query::$limit]].
     */
    public function buildLimit($limit, $offset = 0)
    {
        $hasOffset = $this->hasOffset($offset);
        $hasLimit = $this->hasLimit($limit);
        if ($hasOffset || $hasLimit) {
            // http://technet.microsoft.com/en-us/library/gg699618.aspx
            $sql = 'OFFSET ' . ($hasOffset ? $offset : '0') . ' ROWS';
            if ($hasLimit) {
                $sql .= " FETCH NEXT $limit ROWS ONLY";
            }

            return $sql;
        } else {
            return '';
        }
    }

//	public function resetSequence($table, $value = null)
//	{
//		return '';
//	}

    /**
     * Builds a SQL statement for renaming a DB table.
     * @param string $table the table to be renamed. The name will be properly quoted by the method.
     * @param string $newName the new table name. The name will be properly quoted by the method.
     * @return string the SQL statement for renaming a DB table.
     */
    public function renameTable($table, $newName)
    {
        return "sp_rename '$table', '$newName'";
    }

    /**
     * Builds a SQL statement for renaming a column.
     * @param string $table the table whose column is to be renamed. The name will be properly quoted by the method.
     * @param string $name the old name of the column. The name will be properly quoted by the method.
     * @param string $newName the new name of the column. The name will be properly quoted by the method.
     * @return string the SQL statement for renaming a DB column.
     */
    public function renameColumn($table, $name, $newName)
    {
        return "sp_rename '$table.$name', '$newName', 'COLUMN'";
    }

    /**
     * Builds a SQL statement for changing the definition of a column.
     * @param string $table the table whose column is to be changed. The table name will be properly quoted by the method.
     * @param string $column the name of the column to be changed. The name will be properly quoted by the method.
     * @param string $type the new column type. The {@link getColumnType} method will be invoked to convert abstract column type (if any)
     * into the physical one. Anything that is not recognized as abstract type will be kept in the generated SQL.
     * For example, 'string' will be turned into 'varchar(255)', while 'string not null' will become 'varchar(255) not null'.
     * @return string the SQL statement for changing the definition of a column.
     */
    public function alterColumn($table, $column, $type)
    {
        $type = $this->getColumnType($type);
        $sql = 'ALTER TABLE ' . $this->db->quoteTableName($table) . ' ALTER COLUMN '
            . $this->db->quoteColumnName($column) . ' '
            . $this->getColumnType($type);

        return $sql;
    }

    /**
     * Builds a SQL statement for enabling or disabling integrity check.
     * @param boolean $check whether to turn on or off the integrity check.
     * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
     * @param string $table the table name. Defaults to empty string, meaning that no table will be changed.
     * @return string the SQL statement for checking integrity
     * @throws InvalidParamException if the table does not exist or there is no sequence associated with the table.
     */
    public function checkIntegrity($check = true, $schema = '', $table = '')
    {
        if ($schema !== '') {
            $table = "{$schema}.{$table}";
        }
        $table = $this->db->quoteTableName($table);
        if ($this->db->getTableSchema($table) === null) {
            throw new InvalidParamException("Table not found: $table");
        }
        $enable = $check ? 'CHECK' : 'NOCHECK';

        return "ALTER TABLE {$table} {$enable} CONSTRAINT ALL";
    }
	
    /**
     * Generates a SELECT SQL statement from a [[Query]] object for SQL Server early than 2012.
     * @param Query $query the [[Query]] object from which the SQL statement will be generated.
     * @param array $params the parameters to be bound to the generated SQL statement. These parameters will
     * be included in the result with the additional parameters generated during the query building process.
     * @return array the generated SQL statement (the first array element) and the corresponding
     * parameters to be bound to the SQL statement (the second array element). The parameters returned
     * include those provided in `$params`.
     */
    public function build($query, $params = [])
    {
        $query->prepareBuild($this);

        $params = empty($params) ? $query->params : array_merge($params, $query->params);

        $clauses = [
            $this->buildSelect($query->select, $params, $query->distinct, $query->selectOption),
            $this->buildFrom($query->from, $params),
            $this->buildJoin($query->join, $params),
            $this->buildWhere($query->where, $params),
            $this->buildGroupBy($query->groupBy),
            $this->buildHaving($query->having, $params),
            $this->buildOrderBy($query->orderBy),
        ];

        $sql = implode($this->separator, array_filter($clauses));
		$sql = $this->applyLimit($sql, $query->limit, $query->offset);

        $union = $this->buildUnion($query->union, $params);
        if ($union !== '') {
            $sql = "($sql){$this->separator}$union";
        }

        return [$sql, $params];
    }
	
	/**
	 * This is a port from Prado Framework.
	 *
	 * Overrides parent implementation. Alters the sql to apply $limit and $offset.
	 * The idea for limit with offset is done by modifying the sql on the fly
	 * with numerous assumptions on the structure of the sql string.
	 * The modification is done with reference to the notes from
	 * http://troels.arvin.dk/db/rdbms/#select-limit-offset
	 *
	 * <code>
	 * SELECT * FROM (
	 *  SELECT TOP n * FROM (
	 *    SELECT TOP z columns      -- (z=n+skip)
	 *    FROM tablename
	 *    ORDER BY key ASC
	 *  ) AS FOO ORDER BY key DESC -- ('FOO' may be anything)
	 * ) AS BAR ORDER BY key ASC    -- ('BAR' may be anything)
	 * </code>
	 *
	 * <b>Regular expressions are used to alter the SQL query. The resulting SQL query
	 * may be malformed for complex queries.</b> The following restrictions apply
	 *
	 * <ul>
	 *   <li>
	 * In particular, <b>commas</b> should <b>NOT</b>
	 * be used as part of the ordering expression or identifier. Commas must only be
	 * used for separating the ordering clauses.
	 *   </li>
	 *   <li>
	 * In the ORDER BY clause, the column name should NOT be be qualified
	 * with a table name or view name. Alias the column names or use column index.
	 *   </li>
	 *   <li>
	 * No clauses should follow the ORDER BY clause, e.g. no COMPUTE or FOR clauses.
	 *   </li>
	 * </ul>
	 *
	 * @param string $sql SQL query string.
	 * @param integer $limit maximum number of rows, -1 to ignore limit.
	 * @param integer $offset row offset, -1 to ignore offset.
	 * @return string SQL with limit and offset.
	 *
	 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
	 */
	public function applyLimit($sql, $limit, $offset)
	{
		$limit = $limit!==null ? (int)$limit : -1;
		$offset = $offset!==null ? (int)$offset : -1;
		if ($limit > 0 && $offset <= 0) //just limit
			$sql = preg_replace('/^([\s(])*SELECT( DISTINCT)?(?!\s*TOP\s*\()/i',"\\1SELECT\\2 TOP $limit", $sql);
		elseif($limit > 0 && $offset > 0)
			$sql = $this->rewriteLimitOffsetSql($sql, $limit,$offset);
		return $sql;
	}

	/**
	 * Rewrite sql to apply $limit > and $offset > 0 for MSSQL database.
	 * See http://troels.arvin.dk/db/rdbms/#select-limit-offset
	 * @param string $sql sql query
	 * @param integer $limit $limit > 0
	 * @param integer $offset $offset > 0
	 * @return string modified sql query applied with limit and offset.
	 *
	 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
	 */
	protected function rewriteLimitOffsetSql($sql, $limit, $offset)
	{
		$fetch = $limit+$offset;
		$sql = preg_replace('/^([\s(])*SELECT( DISTINCT)?(?!\s*TOP\s*\()/i',"\\1SELECT\\2 TOP $fetch", $sql);
		$ordering = $this->findOrdering($sql);
		$orginalOrdering = $this->joinOrdering($ordering, '[__outer__]');
		$reverseOrdering = $this->joinOrdering($this->reverseDirection($ordering), '[__inner__]');
		$sql = "SELECT * FROM (SELECT TOP {$limit} * FROM ($sql) as [__inner__] {$reverseOrdering}) as [__outer__] {$orginalOrdering}";
		return $sql;
	}

	/**
	 * Base on simplified syntax http://msdn2.microsoft.com/en-us/library/aa259187(SQL.80).aspx
	 *
	 * @param string $sql $sql
	 * @return array ordering expression as key and ordering direction as value
	 *
	 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
	 */
	protected function findOrdering($sql)
	{
		if(!preg_match('/ORDER BY/i', $sql))
			return array();
		$matches=array();
		$ordering=array();
		preg_match_all('/(ORDER BY)[\s"\[](.*)(ASC|DESC)?(?:[\s"\[]|$|COMPUTE|FOR)/i', $sql, $matches);
		if(count($matches)>1 && count($matches[2]) > 0)
		{
			$parts = explode(',', $matches[2][0]);
			foreach($parts as $part)
			{
				$subs=array();
				if(preg_match_all('/(.*)[\s"\]](ASC|DESC)$/i', trim($part), $subs))
				{
					if(count($subs) > 1 && count($subs[2]) > 0)
					{
						$name='';
						foreach(explode('.', $subs[1][0]) as $p)
						{
							if($name!=='')
								$name.='.';
							$name.='[' . trim($p, '[]') . ']';
						}
						$ordering[$name] = $subs[2][0];
					}
					//else what?
				}
				else
					$ordering[trim($part)] = 'ASC';
			}
		}

		// replacing column names with their alias names
		foreach($ordering as $name => $direction)
		{
			$matches = array();
			$pattern = '/\s+'.str_replace(array('[',']'), array('\[','\]'), $name).'\s+AS\s+(\[[^\]]+\])/i';
			preg_match($pattern, $sql, $matches);
			if(isset($matches[1]))
			{
				$ordering[$matches[1]] = $ordering[$name];
				unset($ordering[$name]);
			}
		}

		return $ordering;
	}

	/**
	 * @param array $orders ordering obtained from findOrdering()
	 * @param string $newPrefix new table prefix to the ordering columns
	 * @return string concat the orderings
	 *
	 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
	 */
	protected function joinOrdering($orders, $newPrefix)
	{
		if(count($orders)>0)
		{
			$str=array();
			foreach($orders as $column => $direction)
				$str[] = $column.' '.$direction;
			$orderBy = 'ORDER BY '.implode(', ', $str);
			return preg_replace('/\s+\[[^\]]+\]\.(\[[^\]]+\])/i', ' '.$newPrefix.'.\1', $orderBy);
		}
	}

	/**
	 * @param array $orders original ordering
	 * @return array ordering with reversed direction.
	 *
	 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
	 */
	protected function reverseDirection($orders)
	{
		foreach($orders as $column => $direction)
			$orders[$column] = strtolower(trim($direction))==='desc' ? 'ASC' : 'DESC';
		return $orders;
	}
	
}