v.21.1Improvements

Allow EXCEPT in Column Transformer to Accept Regex Strings

Official CH changelog text
Allow column transformer EXCEPT to accept a string as regular expression matcher. This resolves #18685 . #18699 (Amos Bird).
The EXCEPT clause in column transformers now supports string arguments interpreted as regular expressions for matching column names.

Why it matters

This feature enables more flexible and powerful column selection by allowing users to exclude columns based on pattern matching rather than listing them explicitly. It simplifies queries and improves usability when working with dynamically named columns or large schemas.

How to use it

Use the EXCEPT clause with a string argument representing a regular expression to exclude columns matching the pattern in column transformers. For example:

SELECT  EXCEPT('^tmp_.$') FROM table

This will exclude all columns whose names start with "tmp_".

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