In postgres sql, at the time of insert data from select to another table , I have to build a sequence depending upon the session, for every session sequence should have start from 1 and increment by one. when new session inserted sequence should start from 1.

CodePudding user response：

Calculate sequence on insert:

insert into mytable (session, sequence, ...)
values (1, (select count(*)   1 from mytable where session = 1), ...)

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