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;