Mysql 专门针对这种情况？我必须用不止一条sql语句来完成，对吗？如果你计算创建临时表并插入其中所需的语句，那么是的，你不能用一条语句来完成，但实际的更新是在一次快照中完成的。这很好，但是如果你有100多条记录，你会怎么做呢？这对100个值来说很好，但我可能会将i

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专门针对这种情况？我必须用不止一条sql语句来完成，对吗？如果你计算创建临时表并插入其中所需的语句，那么是的，你不能用一条语句来完成，但实际的更新是在一次快照中完成的。这很好，但是如果你有100多条记录，你会怎么做呢？这对100个值来说很好，但我可能会将id/值对存储在一个表中，并使用联接进行更新。这很好，但如果您有100多条记录，您将如何进行操作？这对100个值很好，但我可能会将id/值对存储在一个表中，并使用联接进行更新。

id     name     code
---------------------
1      n1       
2      n2     
3      n3 

id     name     code
---------------------
1      n1       code-1
2      n2       code-2
3      n3       code-3

update table t
    set code = concat('code-', id)
    where id in (1, 2, 3);

update table t
    set code = (case when id = 1 then 'code-1'
                     when id = 2 then 'code-2'
                     when id = 3 then 'code-3'
                end)
    where id in (1, 2, 3);

id       code
-------------
1       code-1
2       code-2
3       code-3

UPDATE original
SET code = temp.code
FROM original INNER JOIN temp
ON original.id = temp.id

  SELECT 1 AS rownum, 'code-1' AS code
  UNION ALL SELECT 2, 'code-2'
  UNION ALL SELECT 3, 'code-3'

  SELECT r.id
       , @rn := @rn + 1 AS rowumn
    FROM mytable r
   CROSS JOIN ( SELECT @rn := 0 ) i
   ORDER BY r.name, r.id

  SELECT t.id
       , t.name
       , t.code AS old_code
       , c.code AS new_code
       , o.rownum
    FROM ( SELECT 1 AS rownum, 'code-1' AS code
           UNION ALL SELECT 2, 'code-2'
           UNION ALL SELECT 3, 'code-3'
         ) c
    JOIN ( SELECT r.id
                , @rn := @rn + 1 AS rowumn
            FROM mytable r
            CROSS JOIN ( SELECT @rn := 0 ) i
            ORDER BY r.name, r.id
         ) o
      ON o.rownum = c.rownum
    JOIN mytable t
      ON t.id = o.id 

  UPDATE ( SELECT 1 AS rownum, 'code-1' AS code
           UNION ALL SELECT 2, 'code-2'
           UNION ALL SELECT 3, 'code-3'
         ) c
    JOIN ( SELECT r.id
                , @rn := @rn + 1 AS rowumn
            FROM mytable r
            CROSS JOIN ( SELECT @rn := 0 ) i
            ORDER BY r.name, r.id
         ) o
      ON o.rownum = c.rownum
    JOIN mytable t
      ON t.id = o.id 
     SET t.code = c.code

    FROM my_new_code_table c

       ( SELECT 21 AS rownum, 'code-21' AS code 
         UNION ALL SELECT 22, 'code-22'
         ... 
         UNION ALL SELECT 40, 'code-40'
       ) c

UPDATE `entry`
JOIN 
( *DEFINE QUERY FOR LOOKUPTABLE HERE* ) as alias
on alias.id=entry.valuetoreplace
SET `valuetoreplace` = alias.newvalue;