需求背景
一个统计接口,前端需要返回两个数组,一个是0-23的小时计数,一个是各小时对应的统计数。
思路 直接使用group by查询要统计的表,当某个小时统计数为0时,会没有该小时分组。思考了一下,需要建立辅助表,只有一列小时,再插入0-23共24个小时
CREATE TABLE hours_list (
hour int NOT NULL PRIMARY KEY
)
先查小时表,再做连接需要查的表,即可将没有统计数的小时填充上0。这里由于需要查多个表中,create_time在每个小时区间内、且SOURCE_ID等于查询条件的统计之和,所以UNION ALL了多张表
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
统计数为0的小时也可以查出来了。
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