SQL sql嵌套case语句
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/3187789/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
sql nested case statements
提问by matt1234
does anyone know whats wrong with this nested select statement? It complains about missing )'s but i can't understand why it doesn't work (i have left off the other bits of the statement)
有谁知道这个嵌套的 select 语句有什么问题？它抱怨缺少 )，但我不明白为什么它不起作用（我忽略了语句的其他部分）
Select
(CASE WHEN REQUESTS.grade_id = 1 THEN
(CASE WHEN ((date_completed-date_submitted)*24*60)<=30 THEN 'Yes'
ELSE 'No'
END)
ELSE CASE WHEN REQUESTS.grade_id = 2 THEN
(CASE ((date_completed-date_submitted)*24*60) <=120 THEN 'Yes'
ELSE 'No'
END)
ELSE CASE WHEN REQUESTS.grade_id = 3 THEN
(CASE ((date_completed-date_submitted)*24*60)<=14400 THEN 'Yes'
ELSE 'No'
END)
END)in_SLA
If i just do
如果我只是这样做
Select
(CASE WHEN REQUESTS.grade_id = 1 THEN
(CASE WHEN ((date_completed-date_submitted)*24*60)<=30 THEN 'Yes'
ELSE 'No'
END)
END) in_sla
It works fine!
它工作正常！
any help is much appreciated
任何帮助深表感谢
M
米
sorry being a tard i'm missing the whens from the nested cases
抱歉，我迟到了，我错过了嵌套案例的时间
回答by Tony Andrews
It should be:
它应该是：
Select
(CASE WHEN REQUESTS.grade_id = 1 THEN
(CASE WHEN ((date_completed-date_submitted)*24*60)<=30 THEN 'Yes'
ELSE 'No'
END)
WHEN REQUESTS.grade_id = 2 THEN
(CASE ((date_completed-date_submitted)*24*60) <=120 THEN 'Yes'
ELSE 'No'
END)
WHEN REQUESTS.grade_id = 3 THEN
(CASE ((date_completed-date_submitted)*24*60)<=14400 THEN 'Yes'
ELSE 'No'
END)
END)in_SLA
i.e. just "WHEN" not "ELSE CASE WHEN" for each case.
即对于每种情况，只是“WHEN”而不是“ELSE CASE WHEN”。
I'd be tempted to simplify to:
我很想简化为：
Select
CASE WHEN (REQUESTS.grade_id = 1 AND (date_completed-date_submitted)*24*60 <= 30)
OR (REQUESTS.grade_id = 2 AND (date_completed-date_submitted)*24*60 <=120)
OR (REQUESTS.grade_id = 3 AND (date_completed-date_submitted)*24*60 <=14400)
THEN 'Yes'
ELSE 'No'
END in_SLA
