SQL Server reducing the length of the string to 8000 characters

Question

I am trying to insert data in a table with column datatype as NTEXT. Ideally it should store more than 8000 characters, but the in my case it is reducing it to

Answer 1

In SQL Server 2017 onwards, there is CONCAT_WS function to perform concatenation easily. You can also read about CONCAT

So, instead of this:

INSERT INTO TMPRESULTS SELECT ('A' + ',' + 'B' + ',' + 'C')

We can have below:

INSERT INTO TMPRESULTS SELECT CONCAT_WS(CAST(N',' AS NVARCHAR(MAX)),'A','B','C'))

I have put sample below from SQL Server 2017 for reference:

CREATE TABLE #tempValue(BigValue NVARCHAR(MAX))

INSERT INTO #tempValue
SELECT CONCAT_WS(CAST(N',' AS NVARCHAR(MAX)),REPLICATE('A',4000),REPLICATE('B',4000),REPLICATE('C',4000))

SELECT LEN(BigValue) FROM #tempValue -- 12002

Also, CONCAT_WS is better for below reasons:

If CONCAT_WS receives arguments with all NULL values, it will return an empty string of type varchar(1).

CONCAT_WS ignores null values during concatenation, and does not add the separator between null values.

Answer 2

This is documented in + (String Concatenation) (Transact-SQL) - Remarks:

If the result of the concatenation of strings exceeds the limit of 8,000 bytes, the result is truncated. However, if at least one of the strings concatenated is a large value type, truncation does not occur.

For a varchar 8,000 bytes would be 8,000 characters, and for a nvarchar 4,000.

All your literal strings in the query INSERT INTO TMPRESULTS SELECT ('A' + ',' + 'B' + ',' + 'C') are non large value types (In fact, they are all a varchar(1)). If you CONVERT/CAST one of them to a varchar(MAX) this would solve the problem:

INSERT INTO TMPRESULTS
SELECT (CONVERT(varchar(MAX),'A') + ',' + 'B' + ',' + 'C');

if you want an nvarchar, make sure you declare your literal strings as a nvarchar too:

INSERT INTO TMPRESULTS
SELECT (CONVERT(nvarchar(MAX),N'A') + N',' + N'B' + N',' + N'C');