Merge pull request #410 from mindsdb/fix-cast-decimal

Support CAST(a AS decimal(x, y))

Author: ea-rus

mindsdb_sql/parser/ast/select/type_cast.py

@@ -3,19 +3,20 @@
 
 
 class TypeCast(ASTNode):
-    def __init__(self, type_name, arg, length=None, *args, **kwargs):
+    def __init__(self, type_name, arg, precision=None, *args, **kwargs):
         super().__init__(*args, **kwargs)
 
         self.type_name = type_name
         self.arg = arg
-        self.length = length
+        self.precision = precision
 
     def to_tree(self, *args, level=0, **kwargs):
-        out_str = indent(level) + f'TypeCast(type_name={repr(self.type_name)}, length={self.length}, arg=\n{indent(level+1)}{self.arg.to_tree()})'
+        out_str = indent(level) + f'TypeCast(type_name={repr(self.type_name)}, precision={self.precision}, arg=\n{indent(level+1)}{self.arg.to_tree()})'
         return out_str
 
     def get_string(self, *args, **kwargs):
         type_name = self.type_name
-        if self.length is not None:
-            type_name += f'({self.length})'
+        if self.precision is not None:
+            precision = map(str, self.precision)
+            type_name += f'({",".join(precision)})'
         return f'CAST({str(self.arg)} AS {type_name})'

mindsdb_sql/parser/dialects/mindsdb/parser.py

@@ -1466,8 +1466,13 @@ def expr_list_or_nothing(self, p):
         pass
 
     @_('CAST LPAREN expr AS id LPAREN integer RPAREN RPAREN')
+    @_('CAST LPAREN expr AS id LPAREN integer COMMA integer RPAREN RPAREN')
     def expr(self, p):
-        return TypeCast(arg=p.expr, type_name=str(p.id), length=p.integer)
+        if hasattr(p, 'integer'):
+            precision=[p.integer]
+        else:
+            precision=[p.integer0, p.integer1]
+        return TypeCast(arg=p.expr, type_name=str(p.id), precision=precision)
 
     @_('CAST LPAREN expr AS id RPAREN')
     def expr(self, p):

mindsdb_sql/parser/dialects/mysql/parser.py

@@ -821,8 +821,13 @@ def expr_list_or_nothing(self, p):
         pass
 
     @_('CAST LPAREN expr AS id LPAREN integer RPAREN RPAREN')
+    @_('CAST LPAREN expr AS id LPAREN integer COMMA integer RPAREN RPAREN')
     def expr(self, p):
-        return TypeCast(arg=p.expr, type_name=str(p.id), length=p.integer)
+        if hasattr(p, 'integer'):
+            precision=[p.integer]
+        else:
+            precision=[p.integer0, p.integer1]
+        return TypeCast(arg=p.expr, type_name=str(p.id), precision=precision)
 
     @_('CAST LPAREN expr AS id RPAREN')
     def expr(self, p):

mindsdb_sql/parser/parser.py

@@ -581,8 +581,13 @@ def expr_list_or_nothing(self, p):
         pass
 
     @_('CAST LPAREN expr AS id LPAREN integer RPAREN RPAREN')
+    @_('CAST LPAREN expr AS id LPAREN integer COMMA integer RPAREN RPAREN')
     def expr(self, p):
-        return TypeCast(arg=p.expr, type_name=str(p.id), length=p.integer)
+        if hasattr(p, 'integer'):
+            precision=[p.integer]
+        else:
+            precision=[p.integer0, p.integer1]
+        return TypeCast(arg=p.expr, type_name=str(p.id), precision=precision)
 
     @_('CAST LPAREN expr AS id RPAREN')
     def expr(self, p):

mindsdb_sql/render/sqlalchemy_render.py

@@ -254,8 +254,8 @@ def to_expression(self, t):
         elif isinstance(t, ast.TypeCast):
             arg = self.to_expression(t.arg)
             type = self.get_type(t.type_name)
-            if t.length is not None:
-                type = type(t.length)
+            if t.precision is not None:
+                type = type(*t.precision)
             col = sa.cast(arg, type)
 
             if t.alias:

tests/test_parser/test_base_sql/test_select_structure.py

@@ -633,7 +633,15 @@ def test_type_cast(self, dialect):
         sql = f"""SELECT CAST(a AS CHAR(10))"""
         ast = parse_sql(sql, dialect=dialect)
         expected_ast = Select(targets=[
-            TypeCast(type_name='CHAR', arg=Identifier('a'), length=10)
+            TypeCast(type_name='CHAR', arg=Identifier('a'), precision=[10])
+        ])
+        assert ast.to_tree() == expected_ast.to_tree()
+        assert str(ast) == str(expected_ast)
+
+        sql = f"""SELECT CAST(a AS DECIMAL(10, 1))"""
+        ast = parse_sql(sql, dialect=dialect)
+        expected_ast = Select(targets=[
+            TypeCast(type_name='DECIMAL', arg=Identifier('a'), precision=[10, 1])
         ])
         assert ast.to_tree() == expected_ast.to_tree()
         assert str(ast) == str(expected_ast)