1，update gzjbk a //gzjbk是表名 a是该表的别名 update是更新语句2，set a.a094=//让gzjbk表中的a094字段等于一个值3，select mc from bm_a093 b where b.bm='00606' and a.a003='00606' and b.bmbm=a.a093 and b.mca.a094
//查询语句
查询bm_a093中的字段mc的值赋给a094 条件是b.bm='00606' and a.a003='00606' and b.bmbm=a.a093 and b.mca.a094就是bm_a093中的bm字段等于00606和gzjbk表中的a...
当存在select 1 from bm_a093 b where b.bm='00606' and a.a003='00606' and b.bmbm=a.a093 and b.mca.a094的时候，把 gzjbk表的a094字段值改成bm_a093 b where b.bm='00606' and a.a003='00606' and b.bmbm=...
