select USER_ID||USER_NAME as a from ecs_user where ROWNUM<10
select USER_ID||'_'||USER_NAME as a from ecs_user where ROWNUM<10 //加间隔符的
select "CONCAT"(USER_ID,USER_NAME) as a from ecs_user where ROWNUM<10
select USER_ID||USER_NAME as a from ecs_user where ROWNUM<10
select USER_ID||'_'||USER_NAME as a from ecs_user where ROWNUM<10 //加间隔符的
select "CONCAT"(USER_ID,USER_NAME) as a from ecs_user where ROWNUM<10
![oracle中的start with connect by用法[图]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)