pingcap/tidb

Built-in function SOUNDEX not supported

Open

#3,930 opened on Jul 28, 2017

View on GitHub
 (4 comments) (0 reactions) (0 assignees)Go (40,090 stars) (6,186 forks)batch import
component/expressionhelp wantedtype/compatibility

Description

Please answer these questions before submitting your issue. Thanks!

  1. What did you do?
create table t1 (id integer, a varchar(100) character set utf8 collate utf8_unicode_ci); 
insert into t1 values (1, 'Test');    
select * from t1 where soundex(a) = soundex('Test');
  1. What did you expect to see?
+------+------+
| id   | a    |
+------+------+
|    1 | Test |
+------+------+
1 row in set (0.01 sec)
  1. What did you see instead?
ERROR 1105 (HY000): line 0 column 31 near "a) = soundex('Test')" (total length 51)
  1. What version of TiDB are you using (tidb-server -V)?

Contributor guide

Tech stack
go
Domain
database
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
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
basic Go knowledgeunderstanding of TiDB expression layer
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
First, identify where built in functions are registered in TiDB. The expression package likely has a file like 'builtin string.go' where string functions are implemented. Look for existing similar functions (e.g., SOUNDEX is a string function). The implementation needs to compute the Soundex code (e.g., using a hash or algorithm as per MySQL standard). Also, add the function to the function registry and ensure it appears in MySQL compatibility tests. Check the issue comments for any additional context or prior attempts.