Merge pull request #10 from mindsdb/lateral-join

Support lateral join

Author: ea-rus

mindsdb_sql_parser/__about__.py

@@ -1,6 +1,6 @@
 __title__ = 'mindsdb_sql_parser'
 __package_name__ = 'mindsdb_sql_parser'
-__version__ = '0.4.1'
+__version__ = '0.5.0'
 __description__ = "Mindsdb SQL parser"
 __email__ = "[email protected]"
 __author__ = 'MindsDB Inc'

mindsdb_sql_parser/lexer.py

@@ -53,7 +53,7 @@ class MindsDBLexer(Lexer):
         GROUP_BY, HAVING, ORDER_BY,
         STAR, FOR, UPDATE,
 
-        JOIN, INNER, OUTER, CROSS, LEFT, RIGHT, ON, ASOF,
+        JOIN, INNER, OUTER, CROSS, LEFT, RIGHT, ON, ASOF, LATERAL,
 
         UNION, ALL, INTERSECT, EXCEPT,
 
@@ -236,6 +236,7 @@ class MindsDBLexer(Lexer):
     LEFT = r'\bLEFT\b'
     RIGHT = r'\bRIGHT\b'
     ASOF = r'\bASOF\b'
+    LATERAL = r'\bLATERAL\b'
 
     # UNION
 

mindsdb_sql_parser/parser.py

@@ -1283,9 +1283,14 @@ def from_table(self, p):
        'OUTER JOIN',
        'LEFT OUTER JOIN',
        'FULL OUTER JOIN',
-       'ASOF JOIN',
-       'ASOF LEFT JOIN',
+       )
+    def join_type(self, p):
+        return ' '.join([x for x in p])
+
+    @_('join_type',
+       'ASOF join_type',
        'LEFT ASOF JOIN',
+       'join_type LATERAL',
        )
     def join_clause(self, p):
         return ' '.join([x for x in p])

tests/test_base_sql/test_select_structure.py

@@ -1293,3 +1293,34 @@ def test_asof_join(self):
             ast = parse_sql(query)
             assert str(ast) == str(expected_ast)
             assert ast.to_tree() == expected_ast.to_tree()
+
+    def test_lateral_join(self):
+        query = f'''
+          select * from table1 a
+          INNER JOIN LATERAL (SELECT *
+			FROM table2 b
+			WHERE a.x=b.x
+			LIMIT 1) b ON true
+        '''
+
+        expected_ast = Select(
+            targets=[Star()],
+            from_table=Join(
+                condition=Constant(True),
+                join_type='INNER JOIN LATERAL',
+                left=Identifier('table1', alias=Identifier('a')),
+                right=Select(
+                    targets=[Star()],
+                    from_table=Identifier('table2', alias=Identifier('b')),
+                    where=BinaryOperation(op='=', args=[
+                        Identifier('a.x'), Identifier('b.x')
+                    ]),
+                    limit=Constant(1),
+                    alias=Identifier('b'),
+                    parentheses=True
+                ),
+            )
+        )
+        ast = parse_sql(query)
+        assert str(ast) == str(expected_ast)
+        assert ast.to_tree() == expected_ast.to_tree()