From cddb036cf95e9ee0955d5154de25a76196dfd407 Mon Sep 17 00:00:00 2001
From: Alexander Makarov <sam@rmcreative.ru>
Date: Wed, 11 Nov 2015 21:05:57 +0300
Subject: [PATCH] Fixes #9790: Fixed `yii\db\sqlite\QueryBuilder` to generate
 proper SQL for UNION

---
 framework/CHANGELOG.md               |  1 +
 framework/db/sqlite/QueryBuilder.php | 52 ++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 4e5ebbaaec..6536c63459 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -24,6 +24,7 @@ Yii Framework 2 Change Log
 - Bug #9707: Fixed Memcache duration which exceeds 30 days (vernik91)
 - Bug #9714: Fixed `yii\rbac\PhpManager::updateItem()` unable to save users assignments (rezident1307)
 - Bug #9754: Fixed `yii\web\Request` error when path info is empty (dynasource)
+- Bug #9790: Fixed `yii\db\sqlite\QueryBuilder` to generate proper SQL for UNION (romeOz, samdark)
 - Bug #9791: Fixed endless loop on file creation for non-existing device letters on windows (lukos, cebe)
 - Bug #9874: Fixed outputting exception stacktrace in non-debug mode when `Response::FORMAT_RAW` is used (nainoon)
 - Bug #9883: Passing a single `yii\db\Expression` to `Query::select()` or `::addSelect()` was not handled correctly in all cases (cebe)
diff --git a/framework/db/sqlite/QueryBuilder.php b/framework/db/sqlite/QueryBuilder.php
index ab4c034da4..763ebdee3f 100644
--- a/framework/db/sqlite/QueryBuilder.php
+++ b/framework/db/sqlite/QueryBuilder.php
@@ -356,4 +356,56 @@ class QueryBuilder extends \yii\db\QueryBuilder
 
         return '(' . implode($operator === 'IN' ? ' OR ' : ' AND ', $vss) . ')';
     }
+
+    /**
+     * @inheritdoc
+     */
+    public function build($query, $params = [])
+    {
+        $query = $query->prepare($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),
+        ];
+
+        $sql = implode($this->separator, array_filter($clauses));
+        $sql = $this->buildOrderByAndLimit($sql, $query->orderBy, $query->limit, $query->offset);
+
+        $union = $this->buildUnion($query->union, $params);
+        if ($union !== '') {
+            $sql = "$sql{$this->separator}$union";
+        }
+
+        return [$sql, $params];
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function buildUnion($unions, &$params)
+    {
+        if (empty($unions)) {
+            return '';
+        }
+
+        $result = '';
+
+        foreach ($unions as $i => $union) {
+            $query = $union['query'];
+            if ($query instanceof Query) {
+                list($unions[$i]['query'], $params) = $this->build($query, $params);
+            }
+
+            $result .= ' UNION ' . ($union['all'] ? 'ALL ' : '') . ' ' . $unions[$i]['query'];
+        }
+
+        return trim($result);
+    }
 }