Sun Chenyang

Results 13 issues of Sun Chenyang

## Proposed changes Issue Number: close #xxx

## Proposed changes I cherry-picked the regression test cases for issues fixed in branch-2.0 and branch-2.1 to ensure the correctness of the master branch. #41200 #41297 #40425 #40630

## Proposed changes ``` select count(b) from test where b is null ``` - Even if the column "b" has produced a result through index calculation, t is still necessary...