Question

SELECT 
(SELECT mainop 
FROM data_final2 
WHERE (id = A.id) 
AND (os = 1 and test = 2 and mainop BETWEEN 0 AND 500)) AS op1, 

(SELECT mainop 
FROM data_final2 
WHERE (id = A.id) 
AND (os = 1 and test = 2 and mainop BETWEEN 500 AND 1000)) AS op2, 

(SELECT mainop 
FROM data_final2 
WHERE (id = A.id) 
AND (os = 1 and test = 2 and mainop BETWEEN 1001 AND 1500)) AS op3 

FROM data_final2 AS A WHERE A.mainop BETWEEN 0 AND 500 OR A.mainop BETWEEN 500 AND 1000 OR A.mainop BETWEEN 1001 AND 1500

我想在单个SQL查询中编写此查询，而不使用每个输出％来自总计数的子查询。

还想从输出中删除Null

[{"name":"op1","data":[229,null,null,268,null,3

Answer 1

您可以使用CASE语句根据同一列中的多个条件显示数据。

SELECT
    CASE 
        WHEN mainop BETWEEN 0 AND 500
            AND os = 1 AND test = 2
            THEN mainop
        ELSE NULL
    END as op1
    , CASE 
        WHEN mainop BETWEEN 501 AND 1000
            AND os = 1 AND test = 2
            THEN mainop
        ELSE NULL
    END as op2
   , CASE 
        WHEN mainop BETWEEN 1001 AND 1500
            AND os = 1 AND test = 2
            THEN mainop
        ELSE NULL
    END as op3
FROM data_final2
WHERE mainop BETWEEN 0 AND 1500

您还可以在同一列上指定多个CASE语句，以生成不同的数据。

<强>更新

重新阅读你的问题后，我认为你实际上可能正在寻找这样的东西：

SELECT 100 * count(CASE 
            WHEN mainop BETWEEN 0 AND 500
                AND os = 1 AND test = 2
                    THEN 1
                ELSE NULL
        END) * 1.0 / (SELECT count(*) FROM data_final2) AS 'op1'
    ,100 * count(CASE 
            WHEN mainop BETWEEN 501 AND 1000
                AND os = 1 AND test = 2
                    THEN 1
                ELSE NULL
        END) * 1.0 / (SELECT count(*) FROM data_final2) AS 'op2'
    ,100 * count(CASE WHEN mainop BETWEEN 1001 AND 1500
                AND os = 1 AND test = 2
                    THEN 1
                ELSE NULL
        END) * 1.0 / (SELECT count(*) FROM data_final2) AS 'op3'
FROM data_final2
WHERE mainop BETWEEN 0 AND 1500

如果您要将此行显示为百分比数字，请查看您的特定RDBMS函数，以将数据转换为适当的类型。

此外，还有SQLFiddle with what the query returns。

如何编写单个SQL查询以从不同条件的同一列中获取多个结果

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