original SQL : select t1.column1,t1.column2,t2.field1,t2.field2 from T_DT_ytb_01 t1 , T_DT_ytb_02 t2 on t1.column1 = t2.field1 after parse SQL: SELECT t1.column1, t1.column2, t2.field1, t2.field2 FROM T_DT_ytb_01 t1, T_DT_ytb_02 t2 What is simple join?