Improved support for UNION.

Author: udan11

src/Components/UnionKeyword.php

@@ -0,0 +1,41 @@
+<?php
+
+/**
+ * `UNION` keyword builder.
+ *
+ * @package    SqlParser
+ * @subpackage Components
+ */
+namespace SqlParser\Components;
+
+use SqlParser\Component;
+use SqlParser\Parser;
+use SqlParser\Token;
+use SqlParser\TokensList;
+
+/**
+ * `UNION` keyword builder.
+ *
+ * @category   Keywords
+ * @package    SqlParser
+ * @subpackage Components
+ * @author     Dan Ungureanu <udan1107@gmail.com>
+ * @license    http://opensource.org/licenses/GPL-2.0 GNU Public License
+ */
+class UnionKeyword extends Component
+{
+
+    /**
+     * @param SelectStatement[] $component The component to be built.
+     *
+     * @return string
+     */
+    public static function build($component)
+    {
+        $ret = array();
+        foreach ($component as $c) {
+            $ret[] = $c->build();
+        }
+        return implode(" UNION ", $ret);
+    }
+}

src/Parser.php

@@ -114,6 +114,12 @@ class Parser
                 'field'     => 'options',
             ),
 
+            // This is used only for building.
+            'UNION'         => array(
+                'class'     => 'SqlParser\\Components\\UnionKeyword',
+                'field'     => 'union',
+            ),
+
             'ALTER'         => array(
                 'class'     => 'SqlParser\\Components\\Expression',
                 'field'     => 'table',
@@ -425,6 +431,18 @@ public function parse()
                      * @var SelectStatement $lastStatement
                      */
                     $lastStatement->union[] = $statement;
+
+                    // if there are no no delimiting brackets, the `ORDER` and
+                    // `LIMIT` keywords actually belong to the first statement.
+                    $lastStatement->order = $statement->order;
+                    $lastStatement->limit = $statement->limit;
+                    $statement->order = null;
+                    $statement->limit = null;
+
+                    // The statement actually ends where the last statement in
+                    // union ends.
+                    $lastStatement->last = $statement->last;
+
                     $inUnion = false;
                     continue;
                 }

src/Statement.php

@@ -122,11 +122,6 @@ public function build()
              */
             $type = $clause[1];
 
-            // Checking if there is any parser (builder) for this clause.
-            if (empty(Parser::$KEYWORD_PARSERS[$name])) {
-                continue;
-            }
-
             /**
              * The builder (parser) of this clause.
              * @var string $class

src/Statements/SelectStatement.php

@@ -99,6 +99,9 @@ class SelectStatement extends Statement
         'PROCEDURE'                     => array('PROCEDURE',   3),
         'INTO'                          => array('INTO',        3),
         'UNION'                         => array('UNION',       3),
+        // These are available only when `UNION` is present.
+        // 'ORDER BY'                      => array('ORDER BY',    3),
+        // 'LIMIT'                         => array('LIMIT',       3),
     );
 
     /**

src/Utils/Query.php

@@ -533,6 +533,14 @@ public static function getClause($statement, $list, $clause, $type = 0, $skipFir
          */
         $clauses = array_flip(array_keys($statement::$CLAUSES));
 
+        // This is a cheap fix for `SELECT` statements that contain `UNION`.
+        // Replacing the `ORDER BY` or `LIMIT` clauses should replace the last
+        // clause.
+        if (!empty($statement->union)) {
+            $clauses['ORDER BY'] = count($clauses) + 1;
+            $clauses['LIMIT'] = count($clauses) + 2;
+        }
+
         /**
          * Lexer used for lexing the clause.
          * @var Lexer $lexer
@@ -552,10 +560,9 @@ public static function getClause($statement, $list, $clause, $type = 0, $skipFir
         $clauseIdx = $clauses[$clauseType];
 
         $firstClauseIdx = $clauseIdx;
-
         $lastClauseIdx = $clauseIdx + 1;
 
-        // Determining the behaviour of this function.
+        // Determining the behavior of this function.
         if ($type === -1) {
             $firstClauseIdx = -1; // Something small enough.
             $lastClauseIdx = $clauseIdx - 1;

tests/Utils/QueryTest.php

@@ -385,6 +385,21 @@ public function testReplaceClause()
                 'WHERE film_id > 0'
             )
         );
+
+        $parser = new Parser(
+            'select supplier.city, supplier.id from supplier '
+            . 'union select customer.city, customer.id from customer'
+        );
+        $this->assertEquals(
+            'select supplier.city, supplier.id from supplier '
+            . 'union select customer.city, customer.id from customer'
+            . ' ORDER BY city ',
+            Query::replaceClause(
+                $parser->statements[0],
+                $parser->list,
+                'ORDER BY city'
+            )
+        );
     }
 
     public function testReplaceClauseOnlyKeyword()