Difference among these Three

Question

1. select count(*)count(1)columnname(*) from table in sql server.

Jignesh Trivedi · Answer

Hi There is no difference in output. but as a performance tip all experts are suggest to use count(1) or Count(columnname) instead of Count(*) I think for count(1) Internal mechanism of SQL server check whether the row exist or not for Count(*) it will fetch whole row and returns row count. it may be execution plan are different.

Munesh Sharma · Answer

This is very nice question. You go on this link A nd another difference is that count(1) it is faster.