Question

我有两张桌子......比如块和过程

过程：

    P_ID    P_NAME
    ----    ------
   1     x1p1 
   2     x1p4 
   3     x1p8 
   4     x2p1 
   5     x3p4 
   6     x3py

块：

B_ID           BLOCK_NAME                     P_ID  
------   -------------------------------     ------
     1     x1p1ef......ldoddr60maew......    (null)
     2     x1p4fr......ldoddr60mans......    (null)
     3     x1p8jg......ldoddr80maew......    (null)
     4     x1p4gh......ldoddr80mans......    (null)
     5     x1p8mj......ldoyyyyy20ma......    (null)
     6     x2p1ad......ldoyyyyy30maisclk.... (null)
     7     x3p4da......ldoyyyyy30ma......    (null)
     8     x3p4we......ldozzzzz20ma......    (null)
     9     x3pxtu......ldozzzzz40ma......    (null)
    10     x3pxte......ldozzzzz60ma......    (null)

Blocks表中的P_ID是引用Process表中P_ID的外键，它是主键。

现在我想更新Blocks.P_ID = Process.P_ID的值，如果Blocks.BLOCK_NAME 喜欢 Process.P_NAME

我试过

UPDATE Blocks INNER JOIN Process 
ON (Blocks.BLOCK_NAME=Process.P_NAME) 
SET Blocks.P_ID=Process.P_ID 
WHERE Blocks.BLOCK_NAME LIKE CONCAT('%',Process.P_NAME,'%')

对于所有记录，表的Blocks.P_ID更新为1。我把Blocks表作为：

B_ID           BLOCK_NAME                     P_ID  
------   -------------------------------     ------
     1     x1p1ef......ldoddr60maew......      1
     2     x1p4fr......ldoddr60mans......      1 
     3     x1p8jg......ldoddr80maew......      1
     4     x1p4gh......ldoddr80mans......      1
     5     x1p8mj......ldoyyyyy20ma......      1
     6     x2p1ad......ldoyyyyy30maisclk....   1

但我期待这个：

B_ID           BLOCK_NAME                     P_ID  
------   -------------------------------     ------
     1     x1p1ef......ldoddr60maew......      1
     2     x1p4fr......ldoddr60mans......      2 
     3     x3p4jg......ldoddr80maew......      5
     4     x1p4gh......ldoddr80mans......      2
     5     x1p8mj......ldoyyyyy20ma......      3
     6     x2p1ad......ldoyyyyy30maisclk....   4

我不知道我哪里出错了...有人可以帮帮我吗？在此先感谢... !!

Answer 1

你非常接近。

您应该使用ANSI连接语法并将LIKE条件放在ON子句中

UPDATE blocks b JOIN process p
    ON b.block_name LIKE CONCAT(p.p_name, '%')
   SET b.p_id = p.p_id;

或隐式逗号连接语法并将条件放在WHERE子句

中

UPDATE blocks b, process p
   SET b.p_id = p.p_id
 WHERE b.block_name LIKE CONCAT(p.p_name, '%');

另一种方法

UPDATE blocks b JOIN process p
    ON p.p_name = LEFT(b.block_name, CHAR_LENGTH(p.p_name))
   SET b.p_id = p.p_id;

结果：

+------+-----------------------------------+------+
| B_ID | BLOCK_NAME                        | P_ID |
+------+-----------------------------------+------+
|    1 | x1p1ef......ldoddr60maew......    | 1    |
|    2 | x1p4fr......ldoddr60mans......    | 2    |
|    3 | x1p8jg......ldoddr80maew......    | 3    |
|    4 | x1p4gh......ldoddr80mans......    | 2    |
|    5 | x1p8mj......ldoyyyyy20ma......    | 3    |
|    6 | x2p1ad......ldoyyyyy30maisclk.... | 4    |
|    7 | x3p4da......ldoyyyyy30ma......    | 5    |
|    8 | x3p4we......ldozzzzz20ma......    | 5    |
|    9 | x3pxtu......ldozzzzz40ma......    | NULL |
|   10 | x3pxte......ldozzzzz60ma......    | NULL |
+------+-----------------------------------+------+

Answer 2

试试这个：

UPDATE Blocks B 
INNER JOIN PROCESS P ON B.BLOCK_NAME LIKE CONCAT(P.P_NAME + '%')
SET B.P_ID=P.P_ID;

MySql-使用两个表之间的更新

2 个答案: