How to add variables in Dynamic Sql, not concatenate them?

Question

I have the following dynamic sql statement where I want to add @StartRowIndex + @MaximumRows and subtract 1 from it. I am unclear on where to put the single quotes in the statement. Here it is:

SET @sql = @sql + ' SELECT *
 FROM
LicenseInfo
WHERE RowNum 
BETWEEN ' + @StartRowIndex + ' AND ' + 
'(' + @StartRowIndex + @MaximumRows + ')'  -  1
+ ' ORDER BY cnt desc'

Answer 1

Create new variable @EndRowIndex and calculate it before you construct the dynamic sql statement.

Something like:

DECLARE @EndRowIndex int

SET @EndRowIndex = @StartRowIndex + @MaximumRows - 1

SET @sql = @sql + ' SELECT *
 FROM
LicenseInfo
WHERE RowNum 
BETWEEN ' + @StartRowIndex + ' AND ' + @EndRowIndex 
+ ' ORDER BY cnt desc'

Answer 2

You need to cast the int parameters into varchar

SET @sql = @sql + ' SELECT *
 FROM
LicenseInfo
WHERE RowNum 
BETWEEN ' + @StartRowIndex + ' AND ' + 
'(' + CAST(@StartRowIndex as varchar(10)) + CAST(@MaximumRows as varchar(10)) + ') - 1  
 ORDER BY cnt desc'

Answer 3

Declare a variable, do the calculation and CAST it to varchar when generating the SQL statement

DECLARE @LastRowIndex int

SET @LastRowIndex = @StartRowIndex + @MaximumRows - 1

SET @sql = @sql + ' 
SELECT *
FROM LicenseInfo
WHERE 1=1
AND RowNum BETWEEN ' + CAST (@StartRowIndex as VarChar) + 
' AND ' + CAST (@LastRowIndex as VarChar)
+ ' ORDER BY cnt DESC'

You have to cast in order to let SQL Server concatenate string values, otherwise it will try to convert the nVarChar to number and try to add them as numerics.