The starttime column in the dbc.dbqlogtbl table is when the query started. FirstRespTime is when the query was completed and the first row of the resultset was returned to the user/application.
Your query, depending upon what other fields you need from dbqlogtbl will look something like this...
SELECT (FIRSTSTEPTIME - Starttime) MINUTE TO SECOND AS ELAPSED FROM dbc.dbqlogtbl
The starttime column in the dbc.dbqlogtbl table is when the query started. FirstRespTime is when the query was completed and the first row of the resultset was returned to the user/application.
Your query, depending upon what other fields you need from dbqlogtbl will look something like this...