#196: Add DatabaseQueryUnion to perform UNION operations

Author: ercanozkaya

code/database/query/union.php

@@ -0,0 +1,206 @@
+<?php
+/**
+ * Kodekit - http://timble.net/kodekit
+ *
+ * @copyright   Copyright (C) 2007 - 2016 Johan Janssens and Timble CVBA. (http://www.timble.net)
+ * @license     MPL v2.0 <https://www.mozilla.org/en-US/MPL/2.0>
+ * @link        https://github.com/timble/kodekit for the canonical source repository
+ */
+
+namespace Kodekit\Library;
+
+/**
+ * Union Database Query
+ *
+ * @author  Ercan Ozkaya <https://github.com/ercanozkaya>
+ * @package Kodekit\Library\Database\Query
+ */
+class DatabaseQueryUnion extends DatabaseQuerySelect
+{
+    /**
+     * Queries
+     */
+    public $queries = [];
+
+    /**
+     * UNION DISTINCT operation
+     *
+     * @var boolean
+     */
+    public $distinct  = false;
+
+    /**
+     * UNION ALL operation
+     *
+     * @var boolean
+     */
+    public $all = false;
+
+    /**
+     * Add queries for the UNION operation
+     *
+     * @param DatabaseQuerySelect $query
+     * @return $this
+     */
+    public function union(DatabaseQuerySelect $query)
+    {
+        $this->queries[] = $query;
+
+        return $this;
+    }
+
+    /**
+     * Checks if the current query should use UNION ALL
+     *
+     * @return boolean
+     */
+    public function isUnionAllQuery()
+    {
+        return (bool) $this->all;
+    }
+
+    /**
+     * Make the query use UNION ALL
+     *
+     * @return $this
+     */
+    public function all()
+    {
+        $this->all = true;
+
+        return $this;
+    }
+
+    /**
+     * Set columns in all queries
+     *
+     * @param array $columns
+     * @return DatabaseQuerySelect|void
+     */
+    public function columns($columns = array())
+    {
+        foreach ($this->queries as $query) {
+            $query->where($columns);
+        }
+    }
+
+    /**
+     * Set tables in all queries
+     *
+     * @param $table
+     * @return DatabaseQuerySelect|void
+     */
+    public function table($table)
+    {
+        foreach ($this->queries as $query) {
+            $query->table($table);
+        }
+    }
+
+    /**
+     * Set joins in all queries
+     *
+     * @param string $table
+     * @param null   $condition
+     * @param string $type
+     * @return $this|DatabaseQuerySelect
+     */
+    public function join($table, $condition = null, $type = 'LEFT')
+    {
+        foreach ($this->queries as $query) {
+            $query->where($table, $condition, $type);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Set where clauses in all queries
+     *
+     * @param string $condition
+     * @param string $combination
+     * @return $this|DatabaseQuerySelect
+     */
+    public function where($condition, $combination = 'AND')
+    {
+        foreach ($this->queries as $query) {
+            $query->where($condition, $combination);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Set groups in all queries
+     *
+     * @param array|string $columns
+     * @return $this|DatabaseQuerySelect
+     */
+    public function group($columns)
+    {
+        foreach ($this->queries as $query) {
+            $query->group($columns);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Set having constraints in all queries
+     * @param array|string $columns
+     * @return $this|DatabaseQuerySelect
+     */
+    public function having($columns)
+    {
+        foreach ($this->queries as $query) {
+            $query->having($columns);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Render the query to a string
+     *
+     * @return  string  The completed query
+     * @throws \RuntimeException When there are less than 2 queries to combine
+     */
+    public function toString()
+    {
+        if (count($this->queries) < 2) {
+            throw new \RuntimeException("Union needs at least 2 SELECT queries");
+        }
+
+        $queries = [];
+
+        foreach ($this->queries as $query) {
+            $queries[] = '('.$query->toString().')';
+        }
+
+        $driver = $this->getDriver();
+        $glue   = $this->all ? 'UNION ALL' : ($this->distinct ? 'UNION DISTINCT'  : 'UNION');
+        $query  = implode("\n".$glue."\n", $queries);
+
+        if($this->order)
+        {
+            $query .= ' ORDER BY ';
+
+            $list = array();
+            foreach($this->order as $order) {
+                $list[] = $driver->quoteIdentifier($order['column']).' '.$order['direction'];
+            }
+
+            $query .= implode(' , ', $list);
+        }
+
+        if($this->limit) {
+            $query .= ' LIMIT '.$this->offset.' , '.$this->limit;
+        }
+
+        if($this->_parameters) {
+            $query = $this->_replaceParams($query);
+        }
+
+        return $query;
+    }
+}