Handle the case of IN operator used with single value.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@15446 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ZSQLCatalog/SQLCatalog.py

@@ -399,10 +399,12 @@ class Query(QueryMixin):
     elif value is None:
       where_expression.append("%s is NULL" % (key))
     elif isinstance(value, (tuple, list)) and self.operator.upper() == 'IN':
-      if len(value):
+      if len(value) > 1:
         escaped_value_list = [self._quoteSQLString(x) for x in value]
         escaped_value_string = ', '.join(escaped_value_list)
         where_expression.append("%s IN (%s)" % (key, escaped_value_string))
+      elif len(value) == 1:
+        where_expression.append("%s == %s" % (key, self._quoteSQLString(value)))
       else:
         where_expression.append('0') # "foo IN ()" is invalid SQL syntax, so use a "false" value.
     else: