Question

有这样的SQL查询：

SELECT 
(SELECT COUNT(`id`) FROM `table_name` WHERE `custom_id` IN (10,9,8,6,5,4,3,2,1) AND `content` = "test 1") AS test_1 , 
(SELECT COUNT(`id`) FROM `table_name` WHERE `custom_id` IN (10,9,8,6,5,4,3,2,1) AND `content` = "test 2") AS test_2 , 
(SELECT COUNT(`id`) FROM `table_name` WHERE `custom_id` IN (10,9,8,6,5,4,3,2,1) AND `content` = "test 3") AS test_3 
FROM `table_name` GROUP BY `content`

得到这样的结果：

test_1, test_2, test_3
2,      7,      0
2,      7,      0
2,      7,      0
2,      7,      0
2,      7,      0
2,      7,      0
2,      7,      0
2,      7,      0
2,      7,      0
2,      7,      0

需要获得一行结果，如下所示：

test_1, test_2, test_3
2,      7,      0

如何？我的查询有什么问题？

Answer 1

检查这个。

SELECT  distinct 
(SELECT COUNT(`id`) FROM `table_name` WHERE `custom_id` IN (10,9,8,6,5,4,3,2,1) AND `content` = "test 1") AS test_1 , 
(SELECT COUNT(`id`) FROM `table_name` WHERE `custom_id` IN (10,9,8,6,5,4,3,2,1) AND `content` = "test 2") AS test_2 , 
(SELECT COUNT(`id`) FROM `table_name` WHERE `custom_id` IN (10,9,8,6,5,4,3,2,1) AND `content` = "test 3") AS test_3 
FROM `table_name` GROUP BY `content`

Answer 2

您的查询应该像这样重写：

SELECT 
    SUM(CASE WHEN `content` = "test 1" THEN 1 ELSE 0 END) AS test_1,
    SUM(CASE WHEN `content` = "test 2" THEN 1 ELSE 0 END) AS test_2,
    SUM(CASE WHEN `content` = "test 3" THEN 1 ELSE 0 END) AS test_3
FROM 
    `table_name`
WHERE 
    `custom_id` IN (10,9,8,6,5,4,3,2,1);

Answer 3

只需在SELECT语句中添加TOP子句......

SELECT TOP 1
(SELECT COUNT(`id`) FROM `table_name` WHERE `custom_id` IN (10,9,8,6,5,4,3,2,1) AND `content` = "test 1") AS test_1 , 
(SELECT COUNT(`id`) FROM `table_name` WHERE `custom_id` IN (10,9,8,6,5,4,3,2,1) AND `content` = "test 2") AS test_2 , 
(SELECT COUNT(`id`) FROM `table_name` WHERE `custom_id` IN (10,9,8,6,5,4,3,2,1) AND `content` = "test 3") AS test_3 
FROM `table_name` GROUP BY `content`

Answer 4

你在做什么并没有多大意义。您可以从表中选择并按内容分组。这意味着每个内容得到一个结果行（一个用于'测试1'，一个用于'测试2'等）。您的表中似乎有十个不同的内容，因为您显示您有十个结果行。

然后对于每一个这样的行，无论它包含什么，你都在执行你的三个子查询，当然总是会得到相同的结果。

所以：

Datasource(ds => ds.Json(Model).UpdateURL("Templates/Update").InsertURL("Templates/Insert").RemoveURL("Templates/Delete").Adaptor(AdaptorType.RemoteSaveAdaptor))

或更好：

select 
  (select count(*) from table_name 
    where custom_id in (10,9,8,6,5,4,3,2,1) and content = 'test 1') as test_1 , 
  (select count(*) from table_name 
    where custom_id in (10,9,8,6,5,4,3,2,1) and content = 'test 2') as test_2 , 
  (select count(*) from table_name
    where custom_id in (10,9,8,6,5,4,3,2,1) and content = 'test 3') as test_3 ;

需要通过subselect获得一行结果

4 个答案: