Description and function of SQL set nocount on

Set nocount
The returned results do not contain information about the number of rows affected by the transact-SQL statement.

Syntax
Set nocount {on | off}

Note
When set nocount is on, no count is returned (indicating the number of rows affected by the transact-SQL statement ). When set nocount is off, return the count.

Even if set nocount is on, the @ rowcount function is updated.

When set nocount is on, the done_in_proc information of each statement in the stored procedure is not sent to the client. When you use a utility provided by Microsoft SQL server to execute a query) "Nn rows affected" is not displayed in the query results at the end ".

If some statements contained in the stored procedure do not return much actual data, this setting greatly reduces network traffic and significantly improves performance.

Set nocount is set during execution or runtime, rather than during analysis.

Permission
The Set nocount permission is granted to all users by default.

Conclusion: Set nocount on should be added to the header of the stored procedure, and set nocount off should be added to exit the stored procedure to optimize the stored procedure.