Why is My Nvarchar(Max) Variable Truncated at 4000 Characters?

Unexpected Truncation in Nvarchar(Max) Data

Despite declaring the @SQL1 variable as nvarchar(max), which can store up to 2GB of data, the result is being truncated at 4000 characters. This may seem puzzling, especially considering the vast data capacity of nvarchar(max).

The issue lies in the concatenation of strings within the @SQL1 variable. Before being assigned to @SQL1, the data is stored as a collection of strings with lengths less than 4000 characters. When these strings are concatenated, they retain their maximum length. As a result, the assignment to @SQL1 creates a string with a length of 4000 characters, even though the declared datatype allows for much more.

To avoid this truncation, ensure that all strings being concatenated are of the nvarchar(max) datatype before performing the assignment. This can be achieved by explicitly casting shorter strings to nvarchar(max). For example:

SET @SQL1 = N''
SET @SQL1 = @SQL1 + N'SELECT DISTINCT Venue...'

By casting the constant string as nvarchar(max), the entire string will become nvarchar(max) and the truncation issue will be resolved.

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