I have a repayments table which has 16 rows for each loan that the repayments belong.
Repayments
loanid repid amnt
--------------------
a1 r1 1,100
a1 r2 1,100
| | |
a1 r16 1,105
b2 s1 2,500
b2 s2 2,500
| | |
b2 s16 2,510
| | |
Loans
loanid othercolumns...
-----------------------
a1
b2
|
blahid
|
LoanIds are some string. RepaymentIds too
I'm looking for a query which gives me the first 15 rows from each repayments for every loan.
loanid repid amnt
a1 r1 1,100
a1 r2 1,100
| | |
a1 r15 1,105
b2 s1 2,500
b2 s2 2,500
| | |
b2 s15 2,510
| | |
Is this possible with SQL? and if so, how?
Assuming rep isn't sequential, in which case you can use WHERE rep <= 15
, then you need to introduce a row number per group. MySql does not have a built in row number function like other databases, but you can use user defined variables
to achieve the same result
select *
from (
select loan, rep, amnt, @row:=if(@prevLoan=loan, @row+1, 1) rn, @prevLoan:=loan
from repayments
join (select @row:=0, @prevLoan:=0) t
order by loan, rep
) t
where rn <= 15
if you have some sort of ID in the other table then a simple inner join should do the trick..something like:
select t1.column1, t1.column2
from table1 t1
inner join table2 t2 on t1.id = t2.t1id
limit 15
hope u get it, if not post the columns and table names and i could try to give you the query you need, but this should get u started.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.