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社区首页 >问答首页 >Mysql Group BY with if语句

Mysql Group BY with if语句
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Stack Overflow用户
提问于 2011-11-17 06:15:02
回答 3查看 6K关注 0票数 2

我不确定这是否是您可以在没有嵌套select的单个select语句中完成的事情。

我正在对我的结果进行分组,我想知道整个分组中的某个字段是否包含条件,显示yes。这样,它将只获取组中的第一行,并检查条件,而不是组中的所有行

代码语言:javascript
运行
复制
if(field = 'condition','yes','no') as field_found
EN

回答 3

Stack Overflow用户

发布于 2011-11-17 06:23:45

示例表: id,score

代码语言:javascript
运行
复制
SELECT t1.id, (
  SELECT IF("10" IN (
    SELECT score FROM table t2 WHERE t1.id = t2.id
  ),'yes','no')) 
FROM table t1
GROUP BY t1.id

这行得通吗?

票数 1
EN

Stack Overflow用户

发布于 2011-11-18 03:47:14

由于您已经在执行group by,因此您应该能够添加一个MAX()作为具有您期望的条件的列,并将其添加到组中……比如

代码语言:javascript
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select 
      MAX( if( field LIKE '%condition%','1', '2' )) as ExtraOrderBy,
      First_Name,
      Last_Name,
      ... rest of query ...
   group by
      customers.Customer_ID
   order by
      1

在本例中,order by是SQL列表中的序数列,而不是显式地重新键入MAX( IF() )条件...因此,如果条件为真,则将其标记为"1",否则"2“将使所有符合条件的项浮动到列表的顶部...然后,您可以按其他内容进行子排序,如姓氏、名字或您查询过的其他字段。

票数 1
EN

Stack Overflow用户

发布于 2011-11-18 03:00:30

代码语言:javascript
运行
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if(GROUP_CONCAT(field) LIKE '%condition%','yes','no')

SELECT first_name,last_name, CONCAT(physical_address," ",physical_address2," ",city, " ",zip) as address, MONTHNAME(install_date) as billing_month, IFNULL(status.quantity,0) as total_measures_instalclient2d,IFNULL(client1_measures,"") as client1_measures,IFNULL(client2_measures,"") as client2_measures,IFNULL(client1_quantity,0) as client1_quantity,IFNULL(client2_quantity,0) as client2_quantity,if(GROUP_CONCAT(measure_list.measure_type) LIKE '%Outreach/ Assessment%','yes','no') as outreach_invoiced,GROUP_CONCAT(IF(client='Client1',CONCAT(percent*100,"%-",measure_list.measure_type),NULL)) as client1_percent,GROUP_CONCAT(IF(client='Client2',CONCAT(percent*100,"%-",measure_list.measure_type),NULL)) as client2_percent,work_order.notes FROM customers
INNER JOIN measure on measure.customer_id = customers.customer_id
INNER JOIN measure_list on measure_list.measure_list_id = measure.measure_list_id
INNER JOIN work_order on work_order.work_order_id = measure.work_order_id
INNER JOIN billing on billing.workmanship = work_order.workmanship AND billing.measure_type = measure_list.measure_type
LEFT JOIN (
SELECT customers.customer_id,SUM(quantity) as quantity,GROUP_CONCAT(IF(client='Client1',measure_description,NULL)) as client1_measures,GROUP_CONCAT(IF(client='client2',measure_description,NULL)) as client2_measures,SUM(IF(client='client1',quantity,0)) as client1_quantity,SUM(IF(client='client2',quantity,0)) as client2_quantity FROM customers
INNER JOIN measure on measure.customer_id = customers.customer_id
INNER JOIN measure_list on measure_list.measure_list_id = measure.measure_list_id
INNER JOIN work_order on work_order.work_order_id = measure.work_order_id
INNER JOIN billing on billing.workmanship = work_order.workmanship AND billing.measure_type = measure_list.measure_type
WHERE measure_list.measure_type NOT IN ('measure1','measure2')
GROUP BY customers.customer_id
) as status on status.customer_id = customers.customer_id
WHERE measure_list.measure_type IN ('measure1','measure2')
GROUP BY customers.customer_id
票数 0
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页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接:

https://stackoverflow.com/questions/8159504

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