[英]Inner join with multiple conditions across multiple tables (SQL)
寻找有关将多个SQL查询合并到一个多部分内部连接语句中的建议。
我有以下三个表( Table :Columns):
VisitTable :pid,visit_date,visit_start_datetime,visit_end_datetime,visit_id,visit_type,visit_length,visit_rating
CondTable:PID,cond_date,cond_datetime,cond_id,cond_type,cond_length,cond_rating
ProdTable :pid,prod_id,prod_date,prod_start_datetime,prod_end_datetime,prod_rating,prod_price
我有以下原子SQL查询:
select pid, visit_date, visit_start_datetime, visit_end_datetime
from VisitTable
where visit_id = XYZ AND visit_start_datetime > '01/01/2009'
select pid, cond_date, cond_datetime
from CondTable
where cond_id in (ABC, DEF, GHI)
select pid, prod_date, prod_start_datetime, prod_end_datetime
from ProdTable
where prod_id in (123, 456, 789)
让我们将第一个查询( Temp1
),第二个查询( Temp2
)和第三个查询( Temp3
)的结果Temp3
。
我想在pid
Temp2
Temp1
与Temp2
进行内部连接,其中( Temp1.visit_start_datetime <= Temp2.cond_datetime <= Temp1.visit_end_datetime
),即在Temp2.cond_datetime
在[Temp1.visit_start_datetime, Temp1.visit_end_datetime]
范围内的情况下那pid
。 我们将此Temp4
的结果称为Temp4
。
然后我想借此结果( Temp4
)中并用内加入它Temp3
上pid
其中Temp3.prod_start_datetime
是在范围[Temp1.visit_start_datetime, Temp1.visit_end_datetime]
问题:
我尝试了以下语法,但它是不正确的:
select pid, visit_date, visit_start_datetime, visit_end_datetime
from VisitTable
where visit_id = XYZ AND visit_start_datetime > '01/01/2009'
left join
(select pid, cond_date, cond_datetime
from CondTable
where cond_id in (ABC, DEF, GHI)) Temp2 on Temp2.pid = VisitTable.pid
where Temp2.cond_datetime between VisitTable.visit_start_datetime and VisitTable.visit_end_datetime
left join
(select pid, prod_date, prod_start_datetime, prod_end_datetime
from ProdTable
where prod_id in (123, 456, 789)) Temp3 on Temp3.pid = VisitTable.pid
where Temp3.prod_start_datetime between VisitTable.visit_start_datetime and VisitTable.visit_end_datetime
在第一个原子SQL查询中,我最初尝试将WHERE
子句与visit_date
一起使用,但收到一条错误消息,指出“ visit_date”是一个整数。 然后,我尝试使用visit_start_datetime
,它接受了条件>= '01/01/2009'
visit_start_datetime
>= '01/01/2009'
。 为什么会发生这种情况,无论如何我可以改用visit_date
?
构造此查询后,如何按日期分组并计算每个日期出现的条目数?
谢谢!
请尝试使用以下SQL,您的日期格式无法通过SQL查询理解。
select Temp1.* from
(
select pid, visit_date, visit_start_datetime, visit_end_datetime
from VisitTable
where visit_id = XYZ AND visit_start_datetime > '2009-01-01'
) as Temp1 inner join
(
select pid, cond_date, cond_datetime
from CondTable
where cond_id in (ABC, DEF, GHI)
) as Temp2 on Temp1.pid = Temp2.pid
and Temp1.visit_start_datetime <= Temp2.cond_datetime and Temp2.cond_datetime <= Temp1.visit_end_datetime
inner join
(
select pid, prod_date, prod_start_datetime, prod_end_datetime
from ProdTable
where prod_id in (123, 456, 789)
) as Temp3 on Temp1.pid = Temp3.pid
and Temp1.visit_start_datetime <= Temp3.prod_start_datetime and Temp3.prod_start_datetime <= Temp1.visit_end_datetime
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