topic Re: Selecting Previously Updated Row in Current Row (within the same query)? in Integration and Testing

Selecting Previously Updated Row in Current Row (within the same query)?

AlessioDidier — Tue, 02 Feb 2021 15:07:51 GMT

I have a situation where I need to select a previous row's UPDATED value to be used in calculating the current row's value... and then that is used to calculate the next row's value, so on, and so on...

I am using the LAG function successfully- however, no matter how I write my query it seems to only pull ALL the previous values FIRST, then update each row after that separately. I need it to:

update the current value
move to the next row, grab the previous row's value (from step 1)
update the current row's value using the value from the previous row

I have tried the entire formula all within a single statement, select queries in sub-queries, joins, sub-joins, etc.

Anyone have any advice on how to perform this? Is this a stored procedure of sorts?
Thank you!

Re: Selecting Previously Updated Row in Current Row (within the same query)?

kareem35 — Tue, 06 Apr 2021 10:24:11 GMT

Let us first create a table −mysql> create table DemoTable(Value int); Query OK, 0 rows affected (1.79 sec)Insert some records in the table ...hotmail

Re: Selecting Previously Updated Row in Current Row (within the same query)?

dannielll — Wed, 16 Jun 2021 22:43:20 GMT

Try adding these following tables first

mysql> CREATE TABLE pet (name VARCHAR(20), owner VARCHAR(20), species VARCHAR(20), CHAR(1), birth DATE, death DATE) eliminare account instagram