1? THE
2 (
3 SELECT
4 %SelectClause
5 FROM
6+ ,
6 Source
6.1? AS Alias
7? WHERE Condition
8 )

SelectClause

1.0+ <<---- ,------ <<
1.0 Expression
1.0.1? 
1.0.1 AS Target
1 ITEM Expression
1.0 COUNT
1.0 MAX
1.0 MIN
1.0 SUM
1.1 ( Expression )