Optional aliases for subqueries in FROM

sad-spirit · Aug 29, 2023 · df13663 · df13663
1 parent ac5879a
commit df13663
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Showing 5 changed files with 25 additions and 44 deletions.
diff --git a/Changelog.md b/Changelog.md
@@ -4,13 +4,14 @@
 
 ### Added
 
-Support new syntax of PostgreSQL 16 (as of beta 3)
+Support for new syntax of PostgreSQL 16 (as of beta 3)
  * SQL/JSON functions and expressions:
    * `IS JSON` predicate represented by `nodes\expressions\IsJsonExpression`;
    * Aggregate functions `json_arrayagg()` and `json_objectagg()` represented by `nodes\json\JsonArrayAgg` and
      `nodes\json\JsonObjectAgg`;
    * Constructor functions `json_array()` and `json_object()` represented by
      `nodes\json\JsonArrayValueList`, `nodes\json\JsonArraySubselect`, `nodes\json\JsonObject` classes.
+ * Aliases for subqueries in `FROM` are now optional.
  * `SYSTEM_USER` server variable backed by `nodes\expressions\SQLValueFunction`.
  * `[NO] INDENT` option for `XMLSERIALIZE()` expression.
 

diff --git a/src/sad_spirit/pg_builder/Parser.php b/src/sad_spirit/pg_builder/Parser.php
@@ -3582,17 +3582,11 @@ protected function TableReference(): nodes\range\FromElement
 
     protected function RangeSubselect(): nodes\range\Subselect
     {
-        $token     = $this->stream->getCurrent();
         $reference = new nodes\range\Subselect($this->SelectWithParentheses());
 
-        if (!($alias = $this->OptionalAliasClause())) {
-            throw exceptions\SyntaxException::atPosition(
-                'Subselects in FROM clause should have an alias',
-                $this->stream->getSource(),
-                $token->getPosition()
-            );
+        if (null !== ($alias = $this->OptionalAliasClause())) {
+            $reference->setAlias($alias[0], $alias[1]);
         }
-        $reference->setAlias($alias[0], $alias[1]);
 
         return $reference;
     }

diff --git a/src/sad_spirit/pg_builder/SqlBuilderWalker.php b/src/sad_spirit/pg_builder/SqlBuilderWalker.php
@@ -1166,6 +1166,9 @@ public function walkColumnDefinition(nodes\range\ColumnDefinition $node): string
 
     protected function getFromItemAliases(nodes\range\FromElement $rangeItem): string
     {
+        if (null === $rangeItem->tableAlias && null === $rangeItem->columnAliases) {
+            return '';
+        }
         return ' as'
                . (null !== $rangeItem->tableAlias ? ' ' . $rangeItem->tableAlias->dispatch($this) : '')
                . (
@@ -1179,23 +1182,15 @@ public function walkRangeFunctionCall(nodes\range\FunctionCall $rangeItem): stri
     {
         return ($rangeItem->lateral ? 'lateral ' : '') . $rangeItem->function->dispatch($this)
                . ($rangeItem->withOrdinality ? ' with ordinality' : '')
-               . (
-                    null !== $rangeItem->tableAlias || null !== $rangeItem->columnAliases
-                    ? $this->getFromItemAliases($rangeItem)
-                    : ''
-               );
+               . $this->getFromItemAliases($rangeItem);
     }
 
     public function walkRowsFrom(nodes\range\RowsFrom $rangeItem): string
     {
         return ($rangeItem->lateral ? 'lateral ' : '') . 'rows from('
                . implode(', ', $rangeItem->functions->dispatch($this)) . ')'
                . ($rangeItem->withOrdinality ? ' with ordinality' : '')
-               . (
-                    null !== $rangeItem->tableAlias || null !== $rangeItem->columnAliases
-                    ? $this->getFromItemAliases($rangeItem)
-                    : ''
-               );
+               . $this->getFromItemAliases($rangeItem);
     }
 
     public function walkRowsFromElement(nodes\range\RowsFromElement $node): string
@@ -1226,21 +1221,16 @@ public function walkJoinExpression(nodes\range\JoinExpression $rangeItem): strin
             $sql .= ' ' . $rangeItem->using->dispatch($this);
         }
 
-        return null !== $rangeItem->tableAlias || null !== $rangeItem->columnAliases
-               ? '(' . $sql . ')' . $this->getFromItemAliases($rangeItem)
-               : $sql;
+        $alias = $this->getFromItemAliases($rangeItem);
+        return '' === $alias ? $sql : '(' . $sql . ')' . $alias;
     }
 
     public function walkRelationReference(nodes\range\RelationReference $rangeItem): string
     {
         return (false === $rangeItem->inherit ? 'only ' : '')
                . $rangeItem->name->dispatch($this)
                . (true === $rangeItem->inherit ? ' *' : '')
-               . (
-                   null !== $rangeItem->tableAlias || null !== $rangeItem->columnAliases
-                   ? $this->getFromItemAliases($rangeItem)
-                   : ''
-               );
+               . $this->getFromItemAliases($rangeItem);
     }
 
     public function walkRangeSubselect(nodes\range\Subselect $rangeItem): string
@@ -1354,13 +1344,10 @@ public function walkXmlTable(nodes\range\XmlTable $table): string
         $lines[] = $this->getIndent() . 'columns ' . implode($glue, $this->walkGenericNodeList($table->columns));
 
         $this->indentLevel--;
-        $sql = implode($this->options['linebreak'] ?: ' ', $lines)
-               . $this->options['linebreak'] . $this->getIndent() . ')';
-        if ($table->tableAlias || $table->columnAliases) {
-            $sql .= $this->getFromItemAliases($table);
-        }
 
-        return $sql;
+        return implode($this->options['linebreak'] ?: ' ', $lines)
+               . $this->options['linebreak'] . $this->getIndent() . ')'
+               . $this->getFromItemAliases($table);
     }
 
     public function walkXmlTypedColumnDefinition(nodes\xml\XmlTypedColumnDefinition $column): string

diff --git a/tests/ParseFromClauseTest.php b/tests/ParseFromClauseTest.php
@@ -28,13 +28,13 @@
 };
 use sad_spirit\pg_builder\exceptions\SyntaxException;
 use sad_spirit\pg_builder\nodes\{
+    Star,
     TargetElement,
     FunctionCall,
     ColumnReference,
     Identifier,
     TypeName,
-    QualifiedName
-};
+    QualifiedName};
 use sad_spirit\pg_builder\nodes\expressions\{
     KeywordConstant,
     NumericConstant,
@@ -90,21 +90,26 @@ protected function setUp(): void
     public function testBasicItems(): void
     {
         $list = $this->parser->parseFromList(<<<QRY
-    foo.bar, baz(1, 'string'), (select 'quux') as quux
+    foo.bar, baz(1, 'string'), (select 'quux') as quux, (select * from unaliased)
 QRY
         );
         $select = new Select(new TargetList([new TargetElement(new StringConstant('quux'))]));
         $subselect = new Subselect($select);
         $subselect->setAlias(new Identifier('quux'));
 
+        $select = new Select(new TargetList([new Star()]));
+        $select->from[] = new RelationReference(new QualifiedName('unaliased'));
+        $unaliased = new Subselect($select);
+
         $this->assertEquals(
             new FromList([
                 new RelationReference(new QualifiedName('foo', 'bar')),
                 new RangeFunctionCall(new FunctionCall(
                     new QualifiedName('baz'),
                     new FunctionArgumentList([new NumericConstant('1'), new StringConstant('string')])
                 )),
-                $subselect
+                $subselect,
+                $unaliased
             ]),
             $list
         );
@@ -247,13 +252,6 @@ public function testNoMoreThanTwoDots(): void
         $this->parser->parseFromList('foo.bar.baz.quux');
     }
 
-    public function testSubselectsRequireAnAlias(): void
-    {
-        $this->expectException(SyntaxException::class);
-        $this->expectExceptionMessage('should have an alias');
-        $this->parser->parseFromList("(select 'foo')");
-    }
-
     public function testWithOrdinality(): void
     {
         $list = $this->parser->parseFromList(

diff --git a/tests/SqlBuilderTest.php b/tests/SqlBuilderTest.php
@@ -198,6 +198,7 @@ public function testBuildSelectStatement(): void
                 as three on xyzzy.id = three.xyzzy_id,
      some_function(1, 'two', array[3, 4]) with ordinality as sf (id integer, name text collate somecollation),
      (select five, six, seven from yetanothertable where id = $2) as ya,
+     (select * from unaliased),
      rows from (generate_series(1,5), generate_series(1,10) as (gs integer)) with ordinality,
      xyzzy as a (b,c) tablesample bernoulli (50) repeatable (seed),
      LATERAL XMLTABLE(