sql

Question

表 t1  如下                      t2 如下 
   id   name                    t1name  t1id    
    1     A                        A    null
    2     B                        A    null
    3     C                        A    null
                                   B    null
                                   B    null
                                   C    null  
如何写sql将表t2的t1id字段变成                  t1name  t1id    
                   A       1
                   A       1 
                   A       1
                   B       2 
                   B       2
                   C       3  

Answer 1

update t2 set
  tlid=(select id from t1 where t2.tlname=t1.name);

Answer 2

UPDATE t2 SET tlid =(SELECT id FROM t1 WHERE t2.tlname=t1.name)
和楼上的办法一样的