使用group by子句的SQL Update查询

Question

Name         type       Age
-------------------------------
Vijay          1        23
Kumar          2        26
Anand          3        29
Raju           2        23
Babu           1        21
Muthu          3        27
--------------------------------------

编写查询以将每种类型的最大年龄人名更新为“HIGH”。

还请告诉我，为什么以下查询无效

update table1 set name='HIGH' having age = max(age) group by type;

Answer 1

我已经改变了Derek的脚本，现在它适用于我：

UPDATE table1 AS t 
INNER JOIN 
(SELECT type,max(age) mage FROM table1 GROUP BY type) t1 
ON t.type = t1.type AND t.age = t1.mage 
SET name='HIGH'

Answer 2

您不能直接在更新语句中使用group by。 它必须看起来更像这样：

update t
set name='HIGH'
from table1 t
inner join (select type,max(age) mage from table1 group by type) t1
on t.type = t1.type and t.age = t1.mage;

Answer 3

您可以使用半连接：

SQL> UPDATE table1 t_outer
  2     SET NAME = 'HIGH'
  3   WHERE age >= ALL (SELECT age
  4                       FROM table1 t_inner
  5                      WHERE t_inner.type = t_outer.type);

3 rows updated

SQL> select * from table1;

NAME             TYPE AGE
---------- ---------- ----------
HIGH                1 23
HIGH                2 26
HIGH                3 29
Raju                2 23
Babu                1 21
Muthu               3 27

6 rows selected

您的查询将无法工作，因为您无法通过查询直接在组中比较聚合值和列值。 此外，您无法更新聚合。

Answer 4

你可以使用下面的代码。

Update table1#
inner Join (Select max(age) as age, type from Table1 group by Table1) t ON table.age = t.age#
Set name = 'High'#

Answer 5

由于我查看了这个回复并发现它有点令人困惑，我试验确认以下查询确实有效，证实了Svetlana的高度赞成原帖：

update archives_forum f
inner join ( select forum_id, 
    min(earliest_post) as earliest, 
    max(earliest_post) as latest 
  from archives_topic 
    group by forum_id 
  ) t 
  on (t.forum_id = f.id)
set f.earliest_post = t.earliest, f.latest_post = t.latest;

现在你知道......我也是。

Answer 6

试试这个

update table1 set name='HIGH' having age in(select max(age) from table1 group by type);

Answer 7

update table1 set Name='HIGH' where Age in(select max(Age) from table1)

Answer 8

UPDATE table1 SET name = 'HIGH' WHERE age IN (SELECT MAX(age) FROM table1 GROUP BY name)

Answer 9

您不能将GroupBy子句用于Update语句。 在此期间您将不得不使用子查询

Update table1
Set name = 'High'
From table1 
Join (Select max(age), type from Table1 group by Table1) t ON table1.age = t.age