Add orderBy function.
Add duplication attribute (all or distinct).
Add duplication attribute state into join-state.
Remove old comments.
Add shows function for duplication attribute.
Add duplication attribute to join-state.
Add duplication attribute structure to query.
Bugfix of generating SQL string.
Simplify around 'asColumnN'.
Use identity to simplify definitions.
Update to use monadic ColumnSQL.
Un-export stringFromColumnSQL.
Update haddocks.
Add definitions to specify duplication attribute.
Add {distinct, all} attribute to set binary operations.