SET 1 symbol instead whole string in varchar value

Question

SET 1 symbol instead whole string in varchar value

koles2004

Old Hand

Points: 316
More actions
June 12, 2015 at 7:47 am

#304887

I have such Function:
IF EXISTS (SELECT * FROM sys.objects WHERE name = 'TwoDigitsNumber' AND type = 'FN')
DROP FUNCTION MinimumOFThree;
GO
CREATE FUNCTION TwoDigitsNumber(@a int)
RETURNS nvarchar(20)
AS
BEGIN
DECLARE @STR nvarchar(20);
DECLARE @first int;
DECLARE @second int;
SET @first = @a / 10;
SET @second = @a % 10;
if (@first < @second)
BEGIN
SET @STR = 'second';
END
else if (@first > @second)
BEGIN
SET @STR = 'first';
END
else
BEGIN
SET @STR = 'equal';
END
RETURN @STR;
END
DECLARE @a int;
SET @a = 52;
DECLARE @STR nvarchar;
EXEC @STR = TwoDigitsNumber @a;
SELECT @STR;
GO
The only first letter 'f', 's', 'e' is inserted in value instead 'first', 'second', 'equal'.
Why ? How can i insert whole string ? Help me, please.

Viewing 11 posts - 1 through 10 (of 10 total)

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Phil Parkin SSC Guru Points: 246960 More actions · Answer 1

Don't use nvarchar. Use nvarchar(size).

The absence of evidence is not evidence of absence
- Martin Rees
The absence of consumable DDL, sample data and desired results is, however, evidence of the absence of my response
- Phil Parkin

koles2004 Old Hand Points: 316 More actions · Answer 2

I use nvarchar(20) everywhere, but it doesn't help (

Ed Wagner SSC Guru Points: 287026 More actions · Answer 3

Phil hit the nail on the head. With a declared variable, if you don't specify a size for your string, the default length is 1.

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Ed Wagner SSC Guru Points: 287026 More actions · Answer 4

koles2004 (6/12/2015)
I use nvarchar(20) everywhere, but it doesn't help (

When you call your function, you're using the following line to declare your variable:

DECLARE @STR nvarchar;

The function may return properly, but the @STR variable is only populating with the first character of the result.

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koles2004 Old Hand Points: 316 More actions · Answer 5

Where must I specify the length more then 1 symbol ?

Ed Wagner SSC Guru Points: 287026 More actions · Answer 6

Instead of using:

DECLARE @a int;

SET @a = 52;

DECLARE @STR nvarchar;

EXEC @STR = TwoDigitsNumber @a;

SELECT @STR;

GO

Use:

DECLARE @a int;

SET @a = 52;

DECLARE @STR nvarchar(20);

EXEC @STR = TwoDigitsNumber @a;

SELECT @STR;

GO

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koles2004 Old Hand Points: 316 More actions · Answer 7

koles2004

Old Hand

Points: 316

June 12, 2015 at 8:21 am

#1805062

Thank you !

Ed Wagner SSC Guru Points: 287026 More actions · Answer 8

No problem. Glad I could help.

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ChrisM@Work SSC Guru Points: 186127 More actions · Answer 9

koles2004 (6/12/2015)
I have such Function:
IF EXISTS (SELECT * FROM sys.objects WHERE name = 'TwoDigitsNumber' AND type = 'FN')
DROP FUNCTION MinimumOFThree;
GO
CREATE FUNCTION TwoDigitsNumber(@a int)
RETURNS nvarchar(20)
AS
BEGIN
DECLARE @STR nvarchar(20);
DECLARE @first int;
DECLARE @second int;
SET @first = @a / 10;
SET @second = @a % 10;
if (@first < @second)
BEGIN
SET @STR = 'second';
END
else if (@first > @second)
BEGIN
SET @STR = 'first';
END
else
BEGIN
SET @STR = 'equal';
END
RETURN @STR;
END
DECLARE @a int;
SET @a = 52;
DECLARE @STR nvarchar;
EXEC @STR = TwoDigitsNumber @a;
SELECT @STR;
GO
The only first letter 'f', 's', 'e' is inserted in value instead 'first', 'second', 'equal'.
Why ? How can i insert whole string ? Help me, please.

Read about inline table-valued functions. Scalar UDFs have performance issues. Something like this:

DECLARE @a int

SET @a = 25

SELECT Result = CASE WHEN [first] < [second] THEN 'second' WHEN [first] > [second] THEN 'first' ELSE 'equal' END

FROM (SELECT [first] = @a / 10, [second] = @a % 10) d

^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw}

For fast, accurate and documented assistance in answering your questions, please read this article.
Understanding and using APPLY, (I) and (II) Paul White
Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden

Ed Wagner SSC Guru Points: 287026 More actions · Answer 10

Yea, Chris, I was wondering about the purpose of the function myself. I figured it was an example to illustrate the point. Or maybe that was hope on my part. 😉

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