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MySQL按小時查詢數(shù)據(jù),沒有的補0

更新時間：2020年12月18日 11:51:22 作者：Princar

這篇文章主要介紹了MySQL按小時查詢數(shù)據(jù),沒有的補0,本文通過實例代碼給大家介紹的非常詳細，對大家的學(xué)習(xí)或工作具有一定的參考借鑒價值，需要的朋友可以參考下

需求背景

一個統(tǒng)計接口，前端需要返回兩個數(shù)組，一個是0-23的小時計數(shù)，一個是各小時對應(yīng)的統(tǒng)計數(shù)。

思路直接使用group by查詢要統(tǒng)計的表，當(dāng)某個小時統(tǒng)計數(shù)為0時，會沒有該小時分組。思考了一下，需要建立輔助表，只有一列小時，再插入0-23共24個小時

CREATE TABLE hours_list (
 hour int NOT NULL PRIMARY KEY
)

先查小時表，再做連接需要查的表，即可將沒有統(tǒng)計數(shù)的小時填充上0。這里由于需要查多個表中，create_time在每個小時區(qū)間內(nèi)、且SOURCE_ID等于查詢條件的統(tǒng)計之和，所以UNION ALL了多張表

	SELECT
			 t.HOUR,
			 sum(t.HOUR_COUNT) hourCount
			FROM
    (SELECT
     hs. HOUR AS HOUR,
     COUNT(cs.RECORD_ID) AS HOUR_COUNT
    FROM
     cbc_hours_list hs
    LEFT JOIN cbc_source_0002 cs ON HOUR (cs.create_time) = hs. HOUR
    AND cs.create_time > #{startTime}
    AND cs.create_time <= #{endTime}
    <#if sourceId?exists && sourceId !=''>
     AND SOURCE_ID = #{sourceId}
    </#if>
    GROUP BY
     hs. HOUR
    UNION ALL
    SELECT
     hs.HOUR AS HOUR,
     COUNT(cs.RECORD_ID) AS HOUR_COUNT
    FROM
     cbc_hours_list hs
    LEFT JOIN cbc_source_hs cs ON HOUR (cs.create_time) = hs. HOUR
    AND cs.create_time > #{startTime}
    AND cs.create_time <= #{endTime}
    <#if sourceId?exists && sourceId !=''>
     AND SOURCE_ID = #{sourceId}
    </#if>
    GROUP BY
     hs. HOUR
    UNION ALL
    SELECT
     hs.HOUR AS HOUR,
     COUNT(cs.RECORD_ID) AS HOUR_COUNT
    FROM
     cbc_hours_list hs
    LEFT JOIN cbc_source_kfyj cs ON HOUR (cs.create_time) = hs. HOUR
    AND cs.create_time > #{startTime}
    AND cs.create_time <= #{endTime}
    <#if sourceId?exists && sourceId !=''>
     AND SOURCE_ID = #{sourceId}
    </#if>
    GROUP BY
     hs. HOUR
    UNION ALL
    SELECT
     hs.HOUR AS HOUR,
     COUNT(cs.RECORD_ID) AS HOUR_COUNT
    FROM
     cbc_hours_list hs
    LEFT JOIN cbc_source_his_0002 cs ON HOUR (cs.create_time) = hs. HOUR
    AND cs.create_time > #{startTime}
    AND cs.create_time <= #{endTime}
    <#if sourceId?exists && sourceId !=''>
     AND SOURCE_ID = #{sourceId}
    </#if>
    GROUP BY
     hs. HOUR
    UNION ALL
    SELECT
     hs.HOUR AS HOUR,
     COUNT(cs.RECORD_ID) AS HOUR_COUNT
    FROM
     cbc_hours_list hs
    LEFT JOIN cbc_source_his_hs cs ON HOUR (cs.create_time) = hs. HOUR
    AND cs.create_time > #{startTime}
    AND cs.create_time <= #{endTime}
    <#if sourceId?exists && sourceId !=''>
     AND SOURCE_ID = #{sourceId}
    </#if>
    GROUP BY
     hs. HOUR
    UNION ALL
    SELECT
     hs.HOUR AS HOUR,
     COUNT(cs.RECORD_ID) AS HOUR_COUNT
    FROM
     cbc_hours_list hs
    LEFT JOIN cbc_source_his_kfyj cs ON HOUR (cs.create_time) = hs. HOUR
    AND cs.create_time > #{startTime}
    AND cs.create_time <= #{endTime}
    <#if sourceId?exists && sourceId !=''>
     AND SOURCE_ID = #{sourceId}
    </#if>
    GROUP BY
     hs. HOUR) t
   GROUP BY
    t.hour