hermygithub opened a new issue, #2974: URL: https://github.com/apache/drill/issues/2974
**Is your feature request related to a problem? Please describe.** For time-series analysis, I would like to be able to lag columns for more than one position offset. currently the Lag function is restricted to an offset of '1' and does not allow it to be parameterized. using Lag() on a computed column generates nulls. **Describe the solution you'd like** Ideally aligning to the following syntax `lag(expr[, offset[, default]][ IGNORE NULLS])` `Returns expr evaluated at the row that is offset rows before the current row within the window frame; ` https://duckdb.org/docs/sql/functions/window_functions.html#lagexpr-offset-default-ignore-nulls Lag() on a computed column should provide the previous value of the expression outcome ` 'tickpos (Last*)' as 'tickpos (Last*)-0t', LAG('tickpos (Last*)',1) OVER ( PARTITION BY tickpos_instrument_id, tickpos_granularity ORDER BY tickpos_unixtime_upper ) as 'tickpos (Last*)-1t', LAG('tickpos (Last*)-1t',1) OVER ( PARTITION BY tickpos_instrument_id, tickpos_granularity ORDER BY tickpos_unixtime_upper ) as 'tickpos (Last*)-2t', `  **Describe alternatives you've considered** - lagging a lag computed column (this provides nulls) - calculating the unix epoch time of lag time slices and self-joining based on that calculated timestamp - potentially (but not tried) taking the first() element of a time window frame, ordered by timestamp **Additional context** https://issues.apache.org/jira/browse/DRILL-3596 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: dev-unsubscr...@drill.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
