How to replace a value in one field by a value from another field (different column) within the same view table (SQL)?

Question

I'd like to know if it is possible to replace a value from one field by using a value from another column and a different row.

For Example, click this to view the table image.

I'd like the SumRedeemed value 400 in row 15 to be replaced by the value -1*(-395); the value -395 comes from the EarnPointsLeft in row 6 (both have the same CID meaning that they are the same person). Any suggestions?

Answer 1

You need this update statement:

update t
set t.sumredeemed = (-1) * (select earnpointsleft from FifoPtsView where cid = t.cid)
from FifoPtsView t
where t.cid = 5000100008 and t.earnpointsleft = 0

This will work if the select statement will return only 1 row.

Answer 2

you can simply update your table

update t
set t.sumredeemed = ABS(t2.earnpointsleft )
from FifoPtsView t join FifoPtsView t2 on t.cid = t.cid and isnull(t2.earnpointsleft,0)>0

if you want negative values you can remove ABS , please give me your feedbacks