Question

SELECT DISTINCT 
           t1.name as t1_name, 
           MAX(t1.unit) as t1_unit, 
           MAX(t1.id_producer_goods) AS hi_id_producer_goods, 
          t2.name as t2_name 
FROM Table1 t1 
    left join Table2 t2 on t1.id_web_site=t2.id_web_site 
WHERE t1.id='23'  
GROUP BY t1.name

当我运行查询时，出现以下错误：

Column 'Table2.name' is invalid in the select list because it is not contained 
in either an aggregate function or the GROUP BY clause.

如何撰写此查询？

Answer 1

错误很明显，要么使用t2.name的聚合函数，要么将其添加到GROUP BY，这取决于您要查找的所需结果：

SELECT 
  t1.name as t1_name, 
  t2.name as t2_name,
  MAX(t1.unit) as t1_unit, 
  MAX(t1.id_producer_goods) AS hi_id_producer_goods
FROM Table1 hi 
left join Table2 t2 on t1.id_web_site=t2.id_web_site 
WHERE t1.id='23'  
GROUP BY t1.name, t2.name;

错误是有道理的，因为它必须知道每个t2.name组的t1.name选择哪个值？应该选择max，min等，否则GROUP BY。

另外，DISTINCT删除GROUP BY不需要{。}}。

Answer 2

SELECT 
t1.name as t1_name, 
MAX(t1.unit) as t1_unit, 
MAX(t1.id_producer_goods) AS hi_id_producer_goods, 
t2.name as t2_name FROM Table1 hi 
left join Table2 t2 on t1.id_web_site=t2.id_web_site 
WHERE 
t1.id='23'  
GROUP BY t1.name,t2.name

您需要按AGG功能中未使用的所有字段进行分组。等MAX

Answer 3

试试这个

SELECT 
DISTINCT 
t1.name as t1_name, 
MAX(t1.unit) as t1_unit, 
MAX(t1.id_producer_goods) AS hi_id_producer_goods, 
t2.name as t2_name FROM Table1 hi 
left join Table2 t2 on t1.id_web_site=t2.id_web_site 
WHERE 
t1.id='23'  
GROUP BY t1.name,t2.name

您正在使用具有2列的聚合函数，然后您需要在两列上进行分组

Answer 4

我认为这里不需要DISTINCT关键字。

           SELECT 
           t1.name as t1_name, 
           MAX(t1.unit) as t1_unit, 
           MAX(t1.id_producer_goods) AS hi_id_producer_goods, 
          t2.name as t2_name 
FROM Table1 t1 
    left join Table2 t2 on t1.id_web_site=t2.id_web_site 
WHERE t1.id='23'  
GROUP BY t1.name,t2.name

如何在sql查询中使用group？

4 个答案: