select a.column1 || b.column1 from 表1 a, 表2 b字符型类型相加用“||”
select aa.column1+ccc.column1 from 表1 as aainner join 表二 as cccon aa.id=ccc.id
select table1.a1,table2.a2 from table1 ,table2 where table1.column1=table2.column1