sql - 如何在sql中没有值的情况下获得零

Question

我的查询是

SELECT CASE
WHEN clnt_ntnlty =0 THEN 'Aboriginal'
WHEN clnt_ntnlty =1 THEN 'Torres Strait Islander'
WHEN clnt_ntnlty =2 THEN 'Both Aboring & Torres Strait' 
WHEN clnt_ntnlty =3 THEN 'Neither Aboring OR Torres Strait'
ELSE 'Not Provided' END AS Identy,
ISNULL(COUNT(clnt_ntnlty), 0) AS Counts
FROM dbo.clientInfo
group by clnt_ntnlty

我得到的结果是

如果没有 value ，我希望所有（五行）记录为零。我已经尝试过所有人，它不起作用。

Answer 1

您可以有一个子查询，其中包含您想要的四个值并LEFT JOIN对其执行操作。

SELECT  a.Identy,
        COALESCE(b.Counts, 0) Counts
FROM    (
            SELECT 'Aboriginal' Identy
            UNION ALL
            SELECT 'Torres Strait Islander' Identy
            UNION ALL
            SELECT 'Both Aboring & Torres Strait' Identy
            UNION ALL 
            SELECT 'Neither Aboring OR Torres Strait' Identy
        ) a LEFT JOIN
        (
            SELECT  CASE
                        WHEN clnt_ntnlty =0 THEN 'Aboriginal'
                        WHEN clnt_ntnlty =1 THEN 'Torres Strait Islander'
                        WHEN clnt_ntnlty =2 THEN 'Both Aboring & Torres Strait' 
                        WHEN clnt_ntnlty =3 THEN 'Neither Aboring OR Torres Strait'
                        ELSE 'Not Provided' END AS Identy,
                        ISNULL(COUNT(clnt_ntnlty), 0) AS Counts
            FROM dbo.clientInfo
            group by clnt_ntnlty
        ) b ON a.Identy = b.Identy

Answer 2

好的，我对以下脚本并不感到自豪，因为它是一个肮脏的解决方案；合并所有可能的值并减一以删除该加法

SELECT CASE
WHEN cte.clnt_ntnlty =0 THEN 'Aboriginal'
WHEN cte.clnt_ntnlty =1 THEN 'Torres Strait Islander'
WHEN cte.clnt_ntnlty =2 THEN 'Both Aboring & Torres Strait' 
WHEN cte.clnt_ntnlty =3 THEN 'Neither Aboring OR Torres Strait'
ELSE 'Not Provided' END AS Identy,
ISNULL(COUNT(cte.clnt_ntnlty) - 1, 0) AS Counts
FROM (select ID,clnt_ntnlty from dbo.clientInfo
union select 0,'0' as clnt_ntnlty
union select 1, '1' as clnt_ntnlty
union select 2, '2' as clnt_ntnlty
union select 3, '3' as clnt_ntnlty) as cte
group by clnt_ntnlty

更改联合选择以匹配您的架构

Answer 3

SELECT CASE
WHEN clnt_ntnlty =0 THEN 'Aboriginal'
WHEN clnt_ntnlty =1 THEN 'Torres Strait Islander'
WHEN clnt_ntnlty =2 THEN 'Both Aboring & Torres Strait' 
WHEN clnt_ntnlty =3 THEN 'Neither Aboring OR Torres Strait'
ELSE 'Not Provided' END AS Identy,
SUM(CASE WHEN I.clnt_ntnlty IS NOT NULL THEN 1 ELSE 0 END) AS c_ntnlty
FROM 
(VALUES (0),(1),(2),(3),(9)) N (ntnlty) LEFT JOIN
dbo.clientInfo I ON N.ntnlty = ISNULL(I.clnt_ntnlty,9)

GROUP BY N.ntnlty

Answer 4

请试试：

SELECT 
    DISTINCT Identy, 
    COUNT(clnt_ntnlty) OVER (PARTITION BY Identy) Counts
FROM (
        SELECT 0 Val, 'Aboriginal' Identy UNION
        SELECT 1 Val, 'Torres Strait Islander' Identy UNION
        SELECT 2 Val, 'Both Aboring & Torres Strait' Identy UNION
        SELECT 3 Val, 'Neither Aboring OR Torres Strait' Identy 
    ) x left join dbo.clientInfo t on t.clnt_ntnlty=x.Val

Answer 5

如果我正确理解您的问题，那么您想在哪里计算“零”，那么这就是一个简单的答案。

改变 -ISNULL(COUNT(clnt_ntnlty), 0) AS Counts

至 -COUNT(ISNULL(clnt_ntnlty, 0)) AS Counts

如果这不是您要寻找的东西，那么将更具欺骗性。