cast converted into its own ClauseElement so that it can have an explicit compilationrel_0_2_3

function in ANSICompiler
MySQLCompiler then skips most CAST calls since it only seems to support the standard syntax for Date
types; other types now a TODO for MySQL
then, polymorphic_union() function now CASTs null()s to the type corresponding to the columns in the UNION,
since postgres doesnt like mixing NULL with integer types
(long road for that .....)

1 files changed, 9 insertions, 1 deletions

diff --git a/lib/sqlalchemy/databases/mysql.py b/lib/sqlalchemy/databases/mysql.py
index aa05134d0..e32d6f120 100644
--- a/lib/sqlalchemy/databases/mysql.py
+++ b/lib/sqlalchemy/databases/mysql.py
@@ -9,7 +9,6 @@ import sys, StringIO, string, types, re, datetime
 from sqlalchemy import sql,engine,schema,ansisql
 from sqlalchemy.engine import default
 import sqlalchemy.types as sqltypes
-import sqlalchemy.databases.information_schema as ischema
 import sqlalchemy.exceptions as exceptions
 
 try:
@@ -250,6 +249,15 @@ class MySQLDialect(ansisql.ANSIDialect):
 
 class MySQLCompiler(ansisql.ANSICompiler):
 
+    def visit_cast(self, cast):
+        """hey ho MySQL supports almost no types at all for CAST"""
+        if (isinstance(cast.type, sqltypes.Date) or isinstance(cast.type, sqltypes.Time) or isinstance(cast.type, sqltypes.DateTime)):
+            return super(MySQLCompiler, self).visit_cast(cast)
+        else:
+            # so just skip the CAST altogether for now.
+            # TODO: put whatever MySQL does for CAST here.
+            self.strings[cast] = self.strings[cast.clause]
+
     def limit_clause(self, select):
         text = ""
         if select.limit is not None: