Column types refactoring.

sqlbuilder/clause.go

@@ -2,6 +2,22 @@ package sqlbuilder
 
 import "bytes"
 
+type serializeOption int
+
+const (
+	ALIASED = iota
+	FOR_PROJECTION
+)
+
 type Clause interface {
-	SerializeSql(out *bytes.Buffer) error
+	SerializeSql(out *bytes.Buffer, options ...serializeOption) error
+}
+
+func contains(s []serializeOption, e serializeOption) bool {
+	for _, a := range s {
+		if a == e {
+			return true
+		}
+	}
+	return false
 }