Is there a way to persist a variable across a go?

Question

Is there a way to persist a variable across a go?

Declare @bob as varchar(50);
Set @bob = 'SweetDB'; 
GO
USE @bob  --- see note below
GO
INSERT INTO @bob.[dbo].[ProjectVersion] ([DB_Name], [Script]) VALUES (@bob,'1.2')

See this SO question for the 'USE @bob' line.

Answer 1

Temp tables are retained over GO statements, so...

SELECT 'value1' as variable1, 'mydatabasename' as DbName INTO #TMP

-- get a variable from the temp table
DECLARE @dbName VARCHAR(10) = (select top 1 #TMP.DbName from #TMP)
EXEC ('USE ' + @dbName)
GO

-- get another variable from the temp table
DECLARE @value1 VARCHAR(10) = (select top 1 #TMP.variable1 from #TMP)

DROP TABLE #TMP

It's not pretty, but it works

Answer 2

Use a temporary table:

CREATE TABLE #variables
    (
    VarName VARCHAR(20) PRIMARY KEY,
    Value VARCHAR(255)
    )
GO

Insert into #variables Select 'Bob', 'SweetDB'
GO

Select Value From #variables Where VarName = 'Bob'
GO

DROP TABLE #variables
go

Answer 3

The go command is used to split code into separate batches. If that is exactly what you want to do, then you should use it, but it means that the batches are actually separate, and you can't share variables between them.

In your case the solution is simple; you can just remove the go statements, they are not needed in that code.

Side note: You can't use a variable in a use statement, it has to be the name of a database.

Answer 4

Not sure, if this helps

declare @s varchar(50)
set @s='Northwind'

declare @t nvarchar(100)
set @t = 'select * from ' + @s + '.[dbo].[Customers]'

execute sp_executesql @t

Answer 5

I prefer the this answer from this question Global Variables with GO

Which has the added benefit of being able to do what you originally wanted to do as well.

The caveat is that you need to turn on SQLCMD mode (under Query->SQLCMD) or turn it on by default for all query windows (Tools->Options then Query Results->By Default, open new queries in SQLCMD mode)

Then you can use the following type of code (completely ripped off from that same answer by Oscar E. Fraxedas Tormo)

--Declare the variable
:setvar MYDATABASE master
--Use the variable
USE $(MYDATABASE);
SELECT * FROM [dbo].[refresh_indexes]
GO
--Use again after a GO
SELECT * from $(MYDATABASE).[dbo].[refresh_indexes];
GO

Answer 6

you could use dynamic sql, just be aware of security risks with this (not 100% sure on the correct syntex)

declare @bob nvarchar(50)

declare @sql nvarchar(max)
set @bob='SweetDB'
set @sql = 'Use ' + @bob

execute sp_executesql @sql