Merge pull request #5 from mindsdb/asof-join

Asof join support

Author: ea-rus

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,
+        JOIN, INNER, OUTER, CROSS, LEFT, RIGHT, ON, ASOF,
 
         UNION, ALL, INTERSECT, EXCEPT,
 
@@ -234,6 +234,7 @@ class MindsDBLexer(Lexer):
     CROSS = r'\bCROSS\b'
     LEFT = r'\bLEFT\b'
     RIGHT = r'\bRIGHT\b'
+    ASOF = r'\bASOF\b'
 
     # UNION
 

mindsdb_sql_parser/parser.py

@@ -1283,6 +1283,9 @@ def from_table(self, p):
        'OUTER JOIN',
        'LEFT OUTER JOIN',
        'FULL OUTER JOIN',
+       'ASOF JOIN',
+       'ASOF LEFT JOIN',
+       'LEFT ASOF JOIN',
        )
     def join_clause(self, p):
         return ' '.join([x for x in p])

tests/test_base_sql/test_select_structure.py

@@ -1236,3 +1236,22 @@ def test_mixed_join(self):
         ast = parse_sql(query)
         assert str(ast) == str(expected_ast)
         assert ast.to_tree() == expected_ast.to_tree()
+
+    def test_asof_join(self):
+        for join_type in ('asof join', 'left asof join', 'asof left join'):
+            query = f'''
+              select * from table1 a
+               {join_type} table2 b on a.x = b.y
+            '''
+            expected_ast = Select(
+                targets=[Star()],
+                from_table=Join(
+                    left=Identifier('table1', alias=Identifier('a')),
+                    right=Identifier('table2', alias=Identifier('b')),
+                    condition=BinaryOperation(op='=', args=[Identifier('a.x'), Identifier('b.y')]),
+                    join_type=join_type,
+                )
+            )
+            ast = parse_sql(query)
+            assert str(ast) == str(expected_ast)
+            assert ast.to_tree() == expected_ast.to_tree()