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這篇文章主要介紹了MySQL按小時查詢數(shù)據(jù),沒有的補(bǔ)0,本文通過實(shí)例代碼給大家介紹的非常詳細(xì)，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(jì)接口，前端需要返回兩個數(shù)組，一個是0-23的小時計(jì)數(shù)，一個是各小時對應(yīng)的統(tǒng)計(jì)數(shù)。

思路 直接使用group by查詢要統(tǒng)計(jì)的表，當(dāng)某個小時統(tǒng)計(jì)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(jì)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(jì)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

效果

統(tǒng)計(jì)數(shù)為0的小時也可以查出來了。

到此這篇關(guān)于MySQL按小時查詢數(shù)據(jù),沒有的補(bǔ)0的文章就介紹到這了,更多相關(guān)MySQL按小時查詢數(shù)據(jù)內(nèi)容請搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！

來源：腳本之家

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