I don't get any output for this simple PRINT
statement. What am I missing?
DECLARE @team varchar(20)
BEGIN
SELECT @team = TEAM
FROM DISTRIB_LINE
PRINT 'value is' + @team
END
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Sign up to join this communityI don't get any output for this simple PRINT
statement. What am I missing?
DECLARE @team varchar(20)
BEGIN
SELECT @team = TEAM
FROM DISTRIB_LINE
PRINT 'value is' + @team
END
The PRINT statement will print nothing if the expression evaluates to a null. Apparently @team
ends up being null as the result of the preceding statement, causing the PRINT to output nothing. If you want to print something even when the variable is null, use ISNULL or COALESCE:
PRINT 'value is ' + ISNULL(@team, '(null)');
You could also add a filter to the SELECT to ensure that NULLs are skipped (if you want them skipped, that is):
SELECT @team = TEAM
FROM DISTRIB_LINE
WHERE TEAM IS NOT NULL;
However, if the table has no rows or if all TEAM
values are null, this statement will not do any assignment. In this case, if PRINT still outputs nothing, it means @team
was null even before the SELECT. Therefore, you may still need to apply the previous method.
Besides, it is not a good idea to assign a variable this way when a table has many rows, because you have no control of which value will ultimately be assigned. Therefore. Alexei has a point there as well with regard to using TOP, as well as combining it with ORDER BY and, possibly, additional filters.
null
with any string in MSSQL results in a null
string by default - see the setting CONCAT_NULL_YIELDS_NULL
.
– Ian Kemp
Mar 13 '18 at 10:44
PRINT
outputs a message, not a resultset. Try something like the following:
DECLARE @team varchar(20)
SELECT TOP 1 @team = TEAM
FROM DISTRIB_LINE
SELECT @team AS Team
My example contains TOP
because I have ensured that @team
receives a single value. However, its value will not be clear (non-deterministic). The most certain is using a ORDER BY
clause and a WHERE
that enforces a single record).
Your code works on my machine and prints
value is800
SQLFiddle just doesn't print output it seems.
If you try your sample on dbfiddle you get the correct output.
If you just run PRINT 'A';
on SQLFiddle it doesn't print anything either (see here) while it does on DBFiddle.
The implementation details of SQLFiddle aren't clear but I suppose it just suppresses print statements.
value is 800
) - what version are you using? – Ian Kemp Mar 13 '18 at 10:40