pingcap/tidb

Use a better error message for some error in window function.

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#10,551 opened on May 21, 2019

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help wantedpriority/P4type/compatibilitytype/usability

Description

Bug Report

Please answer these questions before submitting your issue. Thanks!

  1. What did you do? If possible, provide a recipe for reproducing the error.
SELECT i, j, SUM(i+j) OVER (ORDER BY jj DESC ROWS UNBOUNDED PRECEDING) foo FROM t;

jj is a column name from table t.

  1. What did you expect to see?
Unknown column 'jj' in 'window order by'
  1. What did you see instead?
Unknown column 'jj' in 'field list'
  1. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

Contributor guide

Tech stack
gosql
Domain
database
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Go programmingSQL window functions
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
85
Research direction
Find the code that generates the error message for 'Unknown column' in window order by clauses. The issue shows the current error is 'Unknown column 'jj' in 'field list'' but the expected is 'Unknown column 'jj' in 'window order by''. Locate the relevant error handling logic in the TiDB source code, likely in the planner or executor for window functions. Change the error message to reflect the context of the window order by clause. Ensure tests pass.