jonahgao opened a new issue, #11303: URL: https://github.com/apache/datafusion/issues/11303
### Is your feature request related to a problem or challenge? Datafusion supports this type of syntax, such as `count(a, b)` and `count(distinct a, b)`. However, its behavior may not be well-defined. A counterintuitive behavior is that `count(distinct a, b)` returns more rows than `count(a, b)`. ```sh create table t(a int, b int) as values(1, NULL), (NULL, 10), (NULL, NULL); > select count(distinct a,b) from t; +-------------------------+ | count(DISTINCT t.a,t.b) | +-------------------------+ | 1 | +-------------------------+ > select count(a,b) from t; +----------------+ | count(t.a,t.b) | +----------------+ | 0 | +----------------+ ``` Additionally, PostgreSQL does not support this type of syntax. MySQL only supports `count(distinct a, b)`, but its result is different from DataFusion. ```sh Server version: 8.3.0 Homebrew mysql> create table t(a int, b int); Query OK, 0 rows affected (0.01 sec) mysql> insert into t values(1, NULL), (NULL, 10), (NULL, NULL); Query OK, 3 rows affected (0.01 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> select count(distinct a,b) from t; +---------------------+ | count(distinct a,b) | +---------------------+ | 0 | +---------------------+ 1 row in set (0.00 sec) ``` ### Describe the solution you'd like _No response_ ### Describe alternatives you've considered _No response_ ### Additional context _No response_ -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
