Bug #108836 update table set b = a, c = b; Inconsistent expected results

• Submitted: 20 Oct 2022 14:36
• Modified: 31 Oct 2022 13:53
• Reporter: heng zhang
• Status: Can't repeat
• Category: MySQL Server
• Severity: S3 (Non-critical)
• Version: 8.0.22
• OS: Any
• CPU Architecture: Any

[20 Oct 2022 14:36] heng zhang

Description:
Use sql statements " update table set b = a, c = b;"

eg.
table T:
A  B  C
1  2  3

When there are only one or two pieces of data, the result is:
A  B  C
1  1  1

When there is a large amount of data, the result is:
A  B  C
1  1  2

How to repeat:
Use sql statements " update table set b = a, c = b;"
More than 1600 pieces of data

Suggested fix:
I have tested oracle and hope the results are all 
A  B  C
1  1  2

[31 Oct 2022 13:53] MySQL Verification Team

Hi Mr. zhang,

Thank you for your bug report.

We tried to repeat it with 8.0.31, but without success.

Hence, we need you to test your SQL on 8.0.31. If you notice the same behaviour, we need your table with all data that show the behaviour.

Once we get all we need, we will change the status of this bug report.