tsql - Using one DECLARE statement for several variables

Question

Is there any difference using one DECLARE statement for declaring all your variables in store procedure or function instead of using the statement for each one.

For example:

DECLARE @INST1 INT 
       ,@INST2 BIGINT
       ,@INST3 DATETIME
       .......
       ,@INSTN INT

and

DECLARE @INST1 INT
DECLARE @INST2 BIGINT
DECLARE @INST3 DATETIME
..................
DECLARE @INSTN INT

I am asking for differences like performance, reducing SQL server caches size and other internal for the server stuff, that I am not familiar with and can make the server job easier.

Answer 1

IHMO，没有区别，因为引擎在任何一种情况下都会实例化关于变量的相同内存。编写代码只是很短的时间，但我更喜欢为每个变量使用 DECLARE，因为代码变得更好阅读