Dynamic SQL Not Converting VARCHAR To INT (shouldn't anyway)

Question

I\'m receiving an error:

Conversion failed when converting the varchar value \'INSERT INTO TableRowCount (IntFieldID, DecimalField) SELECT \'to data t

Answer 1

A better way than trying to concatenate an integer is to pass it in as a strongly-typed parameter:

DECLARE @start INT = 1;

DECLARE @sql NVARCHAR(MAX) = N'INSERT ...
  SELECT @start, COUNT(*) FROM ' + @conn;

EXEC sp_executesql @sql, N'@start INT', @start;

Answer 2

You need to convert your @Start to a varchar.

DECLARE @sql NVARCHAR(MAX)
SET @sql = 'INSERT INTO TableRowCount (IntFieldID, DecimalField)
SELECT ' + CAST(@start as nvarchar(20)) +', COUNT(*)
FROM ' + @conn

SQL Server implicitly converts between datatypes on concatenation or addition based on some fairly complex criteria. Suffice to say if you try to combine an int and a string it will always attempt to convert the string to an int unless you tell it otherwise explicitly.

Below is a conversion chart for your reference from MSDN.