select SUM(Convert(decimal (18, 4), Z)) as Z FROM ReportData rd INNER JOIN sensor_info AS sif ON rd.sensorId = sif.sensor_id WHERE datediff(week, wTime, getdate()) = 0 这个语句是什么意思
时间: 2024-02-14 14:33:43 浏览: 22
这个 SQL 查询语句是用来计算最近一周内,所有 ReportData 和 sensor_info 表中的记录中,字段 Z 的值的总和(SUM),并返回这个总和值。具体解释如下:
1. 查询的主要数据源是 ReportData 表和 sensor_info 表。
2. ReportData 和 sensor_info 表通过 sensorId 字段进行连接(INNER JOIN)。
3. 查询的条件是 wTime 字段和当前日期之间的周数差(datediff(week, wTime, getdate()) = 0),也就是最近一周内的数据。
4. 查询结果是一个单独的值,即 Z 字段的值的总和,这个总和值将使用 SUM 函数计算,并通过 Convert 函数将计算结果转换为 decimal (18, 4) 格式的数据。
简单来说,这个查询语句是用来计算最近一周内 ReportData 和 sensor_info 数据表中 Z 字段值的总和。
相关问题
with basic_data as ( select * from (select c.wha_container_code wha_container_code,c.ins_carrier_code ins_carrier_code,'换装' type from ship_dock_supervision_record_detail c left join ship_dock_supervision_record a on c.dock_supervision_record_id = a.id left join ship_situation b on a.ship_situation_id = b.id where b.document_id = 1661945853862719489 group by c.id order by cast(SUBSTRING_INDEX(c.wha_number,"-",1) as decimal)) aa union all select * from (select a.transportation_tool_no wha_container_code,a.seal_no ins_carrier_code,'原柜' type from `storage`.sto_outbound_loading a left join ship_situation b on a.outbound_id = b.ship_transport_notice_id where b.document_id = 1661945853862719489 and a.transportation_tool_type = 2) bb ) select (@i:=@i+1) AS 'xh',ifnull(max(basic_data.wha_container_code),'TBA') wha_container_code,ifnull(max(basic_data.ins_carrier_code),'TBA') ins_carrier_code from basic_data,(SELECT @i:=0) AS itable where FIND_IN_SET(type,'换装') mysql如何让这句sql,查询不到数据时所有列显示为tba
可以使用IFNULL函数和LEFT JOIN语句来实现。具体语句如下:
```
SELECT (@i:=@i+1) AS 'xh', IFNULL(basic_data.wha_container_code, 'TBA') AS wha_container_code, IFNULL(basic_data.ins_carrier_code, 'TBA') AS ins_carrier_code
FROM (SELECT * FROM
(SELECT c.wha_container_code wha_container_code, c.ins_carrier_code ins_carrier_code, '换装' type
FROM ship_dock_supervision_record_detail c
LEFT JOIN ship_dock_supervision_record a ON c.dock_supervision_record_id = a.id
LEFT JOIN ship_situation b ON a.ship_situation_id = b.id
WHERE b.document_id = 1661945853862719489
GROUP BY c.id
ORDER BY CAST(SUBSTRING_INDEX(c.wha_number,"-",1) AS DECIMAL)) aa
UNION ALL
SELECT * FROM
(SELECT a.transportation_tool_no wha_container_code, a.seal_no ins_carrier_code, '原柜' type
FROM `storage`.sto_outbound_loading a
LEFT JOIN ship_situation b ON a.outbound_id = b.ship_transport_notice_id
WHERE b.document_id = 1661945853862719489 AND a.transportation_tool_type = 2) bb ) basic_data
LEFT JOIN (SELECT @i:=0) AS itable
WHERE FIND_IN_SET(type, '换装')
```
这里使用了LEFT JOIN将basic_data表连接到一个虚拟表,虚拟表中只有一个变量@i,用于生成行号。IFNULL函数用于在查询结果为空时将列值替换为'TBA'。
select sum(t.p_totalnav) as scale,t.publish_date as date from (select fundcode,invest_manager,CAST(p_totalnav AS DECIMAL(22,4)) as p_totalnav,publish_date from app.v_jrcrm_hugo_manageasset)t where strpos(t.invest_manager,'钱亚风云')>0 group by 2 优化SQL
优化思路:
1. 使用JOIN代替子查询:将子查询转化为JOIN语句,可以提高查询效率。
2. 使用DECIMAL代替CAST:在定义表结构的时候,可以将p_totalnav字段的类型定义为DECIMAL,避免在查询时进行类型转换。
3. 使用索引:对invest_manager字段创建索引,可以加快查询速度。
优化后的SQL如下:
SELECT SUM(t.p_totalnav) AS scale, t.publish_date AS date
FROM app.v_jrcrm_hugo_manageasset t
JOIN (SELECT DISTINCT fundcode FROM app.v_jrcrm_hugo_manageasset WHERE invest_manager LIKE '%钱亚风云%') m
ON t.fundcode = m.fundcode
WHERE t.publish_date BETWEEN 'start_date' AND 'end_date'
GROUP BY t.publish_date;
其中,start_date和end_date为查询时间范围。如果invest_manager字段已经创建了索引,可以进一步提高查询效率。