How do I join tables on an update
-
03-07-2019 - |
Question
I have the following query:
select count(L.ID)
from LA inner join L on (LA.leadid = L.ID)
where L.status = 5
and L.city = "cityname"
and Date(LA.Datetime) < Date_Sub(Now(), INTERVAL 6 MONTH);
which looks for records with status 5 in a particular city that are older than 6 months (the date for which is stored in LA). This returns about 4k results. I would like to update the value of the status to 1 on each of those records, and so my update looks like:
update L, LA
set L.status = 1
where L.status = 5
and L.city = "cityname"
and Date(LA.SomeDatetime) < Date_Sub(Now(), INTERVAL 6 MONTH);
but it stalls out and locks the db. I suspect there is a problem because there is no join, but I try something like:
update L, LA
from L inner join LA on (L.OID = LA.leadid)
set L.status = 1
where L.status = 5
and L.syscity = "cityname"
and Date(LA.SomeDatetime) < Date_Sub(Now(), INTERVAL 6 MONTH);
and it obviously won't work because there is no 'from' in an update.
edit> I'm using MySQL
Solution
update L
set L.status = 1
where L.status = 5
and L.city = "cityname"
and EXISTS (
select * from LA
where Date(LA.SomeDatetime) < Date_Sub(Now(), INTERVAL 6 MONTH)
and LA.leadid = L.ID
)
OTHER TIPS
For MySQL
, you may use old join syntax:
UPDATE l, la
SET l.status = 1
WHERE l.status = 5
AND l.city = "cityname"
AND la.leadid = l.id
AND DATE(la.datetime) < DATE_SUB(NOW(), INTERVAL 6 MONTH)
I would do this:
update L
set status = 1
from LA
where L.OID = LA.leadid
and L.status = 5
and L.syscity = "cityname"
and Date(LA.SomeDatetime) < Date_Sub(Now(), INTERVAL 6 MONTH)
See also:
In SQL Server 2005 this will work:
Update L
set L.status = 1
from
L
--
JOIN LA
on (LA.leadid = L.id)
where
L.status = 5
and L.city = "cityname"
and Date(LA.Datetime) < Date_Sub(Now(), INTERVAL 6 MONTH);
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