PadLeft function on Null value

Can you use a padleft function on a null value of a field?

I get this when i try to padleft on a result from a db. This happens only when one of the fields are null.

Public member 'PadLeft' on type 'DBNull' not found.

You need handle the NULL from the database before you pass on to your PadLeft function in your program.

Limno

|||

How would I do that?

Can i set the default value of that field to be an empty string? if so how is that done.

thanks,

|||

This should work for ya in VB.NET

CTYPE("" & {Whatever you are trying to padleft that might be DBNULL} & "",string).padleft( ... )

Basically concatenating a string with DBNULL will return the string in vb.net, so it's a quick and easy way to replace fields with dbnull with an empty string. Then I'm casting the result to a string although it isn't necessary, it helps VS2005 to understand the datatype so that intellisense still works (And you can type .padleft, etc). It'll still work without it, but no intellisense (Atleast it didn't in VS2003, and old habits die hard).

|||

I would handle it in a helper function in your application.

Like:

Function fixNull(ByVal sItemAsObject)AsString

If sItemIs DBNull.ValueThen

fixNull = "-"

Else

fixNull = sItem

EndIf

EndFunction

In your code: PadLeft(fixNull(yourInterestedField...))

Or

you can handle this in the SQL statement. For example:

SELECT CASE WHEN col1isnull THEN'-' ELSE col1 ENDas col1FROM testtable

You can replace '-' with an empty string''(two single quote) if you like.

you can process this field as usaual.

Limno

Padd Character Function To Return Variable Type

All,
I have a UDF for SQL that will padd a varchar value to a specific width and
align left or right. I found this code online somewhere, but the problem is
that it accpets a value up to Varchar(8000) and returns a varchar(8000). I
am writing a query to upload to a mainframe and need fixed-width fields, but
each field is not the same size. I can pass in the correct width to the
function and it padds correctly, but in a DTS transformation to a text file,
it thinks all fields are 8000 characters wide.
I am asking if it is possible to return a variable size data type instead of
a fixed type.
Here is the orig function:
ALTER FUNCTION [dbo].[PaddChar] (
@.ValueToPad varchar(8000),
@.PadCharacter char(1),
@.Justification bit,
@.Width int
)
/ ****************************************
***********************************
*************************
This function allows the USER TO pass IN a string / character value AND it
will padd the value according TO given parameters. The parameters are
AS follows:
@.ValueToPad = Value to be padded BY function.
@.PadCharacter = Character used TO pad a given value.
@.Justification = Justification format bit
0 - Value will be RIGHT justified after padding.
1 - Value will be LEFT justified after padding.
@.Width = Total COLUMN width OF the output after padding.
----
--
NOTE - ALL VALUES passes IN FOR padding must be OF CHAR or
VARCHAR data type.
****************************************
************************************
*************************/
RETURNS varchar(8000) AS
BEGIN
DECLARE @.x int
IF @.ValueToPad IS NULL SET @.ValueToPad = ''
IF @.PadCharacter IS NULL SET @.PadCharacter = ''
SET @.X = @.Width - LEN(@.ValueToPad)
--Right Justify Value
IF @.Justification = 0
BEGIN
SET @.ValueToPad = REPLICATE(@.PadCharacter,@.X) + @.ValueToPad
END
ELSE
--Left Justify Value
BEGIN
SET @.ValueToPad = @.ValueToPad + REPLICATE(@.PadCharacter,@.Width)
END
RETURN @.ValueToPad
END
and what I want basically and which doesn't seem to work, is:
ALTER FUNCTION [dbo].[PaddChar] (
@.ValueToPad varchar(8000),
@.PadCharacter char(1),
@.Justification bit,
@.Width int
)
/ ****************************************
***********************************
*************************
This function allows the USER TO pass IN a string / character value AND it
will padd the value according TO given parameters. The parameters are
AS follows:
@.ValueToPad = Value to be padded BY function.
@.PadCharacter = Character used TO pad a given value.
@.Justification = Justification format bit
0 - Value will be RIGHT justified after padding.
1 - Value will be LEFT justified after padding.
@.Width = Total COLUMN width OF the output after padding.
----
--
NOTE - ALL VALUES passes IN FOR padding must be OF CHAR or
VARCHAR data type.
****************************************
************************************
*************************/
RETURNS varchar(@.Width) AS
BEGIN
DECLARE @.x int
IF @.ValueToPad IS NULL SET @.ValueToPad = ''
IF @.PadCharacter IS NULL SET @.PadCharacter = ''
SET @.X = @.Width - LEN(@.ValueToPad)
--Right Justify Value
IF @.Justification = 0
BEGIN
SET @.ValueToPad = REPLICATE(@.PadCharacter,@.X) + @.ValueToPad
END
ELSE
--Left Justify Value
BEGIN
SET @.ValueToPad = @.ValueToPad + REPLICATE(@.PadCharacter,@.Width)
END
RETURN @.ValueToPad
END
Does anyone have any ideas on this?
Thanks,
NathanWhen I need to export fixed-width fields my approach is a bit
different. I create a view that formats each column the way I need it
to a fixed length, then export from the view. Examples of formatting:
convert(char(30), ItemName) as ItemName
STR(ItemValue,9,2)
Roy|||Thank you, I rarely use CHAR since it does padd for storage in the database,
duh! That worked to replace my instances of the dbo.PaddChar in my query fo
r
all the intstances where I am just padding on the right with spaces.
However, I had to just wrap a couple of them that I am right aligning, or
padding with 0's.
Since my query only pulls back a few rows a day the performance isn't bad.
Thank you again,
Nathan
"Roy Harvey" wrote:

> When I need to export fixed-width fields my approach is a bit
> different. I create a view that formats each column the way I need it
> to a fixed length, then export from the view. Examples of formatting:
> convert(char(30), ItemName) as ItemName
> STR(ItemValue,9,2)
> Roy
>

PAD function in Data Tranformation Editor

I have a value with a float datatype in Excel that is actually a date. For example, the value displays 1272006 for January 27, 2006. I am trying to convert this value to a date. I can do this in several stages using T-SQL by converting the datatype to integer, using replicate to make it eight characters and than using substrings to make it look like 01-27-2006 which SQL Server will recognize as a date.

My problem is that there is nothing similar to a PAD (replicate) function using the Data Tranformation Editor in Integration Services. There is a replicate function but it merely functions to repeat a value. It doesn't appear to perform the same PAD function as the T-SQL replicate does. Here is my formula in T-SQL that works okay.

right(replicate('0', 8) + convert(varchar, cast([Date] as varchar)), 8)

I could do this by creating a staging table but I want to handle the entire transformation process within Integration Services. Can anyone offer me some advice? Thank you.

David

I don't think we have your full statement... I'm not seeing where you convert to a date...

Never-the-less, why not substring the "date" field and then cast it to DT_DBDATETIME?|||Question, how is Jan 1st, 2006, represented?

112006? Or 1012006?|||1012006|||

I'm not able to use the substring because the values varies between seven and eight characters. For example, January 1, 2006 is 1012006 while October 1, 2006 is 10012006. I figure I need to convert the value to eight characters by padding a zero on the left. I then can use a substring to convert it to a SQL Server recognizable date like 01-01-2006.

David

|||

davidg12 wrote:

I'm not able to use the substring because the values varies between seven and eight characters. For example, January 1, 2006 is 1012006 while October 1, 2006 is 10012006. I figure I need to convert the value to eight characters by padding a zero on the left. I then can use a substring to convert it to a SQL Server recognizable date like 01-01-2006.

David

Okay, so then this should be easy... If you want to do this in one derived column (are you guaranteed that the value is a correct and verified date?), then you can do something like:

(DT_DBTIMESTAMP)(SUBSTRING(RIGHT("0" + datefield,8),5,4) + "-" + SUBSTRING(RIGHT("0" + datefield,8),1,2) + "-" + SUBSTRING(RIGHT("0" + datefield,8),3,2) + " 00:00:00")

In an upstream derived column, you could do the "RIGHT("0" + datefield,8)" calculation, and then just use that field in the above expression. It would make it easier to read.
|||

Thank you Phil. This works great.

David

overload function call

Hi,

I want to write one function like that

dbo.function( number , 1 , 2 ) ,

but I would like to overload, and send char or number

dbo.function( number, 'abx' , ' xpto' ).

I would like to keep the same name, Can I do this? or Do I need to write to differents functions

thanks,

Hi Alessandro,

Yes, this can be done. You would use the sql_variant datatype as such:

create function fntest (@.one sql_variant, @.two sql_variant)
returns int
as
begin
declare @.ret int

set @.ret = 0

if (select SQL_VARIANT_PROPERTY(@.one,'BaseType')) = 'int'
begin
set @.ret = 99
end

return (@.ret)
end;

The SQL_VARIANT_PROPERTY function will return the base data type, so you can therefore test for not only int, but varchar etc.

Cheers,

Rob

|||

Hi Rob,

Thank you.... Can I do this for return parameter?

Thanks

|||

Hi Alessandro,

Sure can, in the above example, you'd simply change the returning datatype:

create function fntest2 (@.one sql_variant, @.two sql_variant)
returns sql_variant
as
begin

Cheers,

Rob

|||

Hi Rob,

Yes it is true, but I can send or return float values sql_variant doesn't work for this :(

In fact I want to do this.

funtion ( number (always number) , char/number(param1) , char/number(param2) )

if number = 1

return param1

else param 2

similar to oracle decode, but I dont know how to do, do you have any ideia? Maybe clr function but I think overload function via c# doesn't work as well

thanks,

|||

Hi Alessandro,

I think I understand what you want, and the below will let you do this:

create function fntest2 (@.one sql_variant, @.two sql_variant)
returns sql_variant
as
begin
declare @.ret sql_variant

set @.ret = 0

if (select SQL_VARIANT_PROPERTY(@.one,'BaseType')) = 'int'
begin
set @.ret = @.one
end
else
begin
set @.ret = @.two
end

return (@.ret)
end;

Is that what you were after, or did you mean something else?

Cheers,
Rob

|||

Hi Rob,

Yes, but when you call with float from Select clauses like

select fntest( 1 , value1(float) , value2 (float) )

doesn't work I need to convert, have you tried?

Thanks

|||

Hi Alessandro,

What about the below:

create function fntest2 (@.one int, @.two sql_variant, @.three sql_variant)
returns sql_variant
as
begin
declare @.ret sql_variant

set @.ret = 0

if (select SQL_VARIANT_PROPERTY(@.two,'BaseType')) = 'int'
begin
set @.ret = 'it is an int'
end
else if (select SQL_VARIANT_PROPERTY(@.two,'BaseType')) = 'float'
begin
set @.ret = 'it is a float'
end
--more if else statements here...

return (@.ret)
end;

declare @.f float
set @.f = 123.9982

select tempdb.dbo.fntest2( 1 , @.f , 'another param here' )

This returns the character line "it is a float" as the param @.f is explicity defined as float. If you execute the below line:

select tempdb.dbo.fntest2( 1 , 23.55 , 'another param here' )

0 will be returned as 23.55 is interpreted as type numeric

Cheers,

Rob

|||

Hi Rob,

Woks well, thanks, however when I try doing this

select tempdb.dbo.fntest2( 1 , 23.55 , 'another param here' ) - tempdb.dbo.fntest2( 1 , 23.55 , 'another param here' )

I receive this msg

Operand data type sql_variant is invalid for subtract operator.

thanks,

|||

Hi Alessandro,

Yes, that's correct - you cannot perform mathematical operations on the sql_variant datatype. This makes sense as sql has no idea what type it is: it may be binary, or one may be char, and the other numeric or both may be char, in which case you would receive concatenation of the two char values: probably not what you intended...

You'll need to perform an explicit cast as such:

declare @.a sql_variant,
@.b sql_variant

set @.a = 2;
set @.b = 1;

begin try
select (cast(@.a as int) + cast(@.b as int)) as 'sum'
end try
begin catch
print ERROR_MESSAGE()
end catch

You'll need to include the explicit cast in a try block in order to catch any conversion errors (for example, if @.a is a char value, not int).

Cheers,

Rob

overload function call

Hi,

I want to write one function like that

dbo.function( number , 1 , 2 ) ,

but I would like to overload, and send char or number

dbo.function( number, 'abx' , ' xpto' ).

I would like to keep the same name, Can I do this? or Do I need to write to differents functions

thanks,

Hi Alessandro,

Yes, this can be done. You would use the sql_variant datatype as such:

create function fntest (@.one sql_variant, @.two sql_variant)
returns int
as
begin
declare @.ret int

set @.ret = 0

if (select SQL_VARIANT_PROPERTY(@.one,'BaseType')) = 'int'
begin
set @.ret = 99
end

return (@.ret)
end;

The SQL_VARIANT_PROPERTY function will return the base data type, so you can therefore test for not only int, but varchar etc.

Cheers,

Rob

|||

Hi Rob,

Thank you.... Can I do this for return parameter?

Thanks

|||

Hi Alessandro,

Sure can, in the above example, you'd simply change the returning datatype:

create function fntest2 (@.one sql_variant, @.two sql_variant)
returns sql_variant
as
begin

Cheers,

Rob

|||

Hi Rob,

Yes it is true, but I can send or return float values sql_variant doesn't work for this :(

In fact I want to do this.

funtion ( number (always number) , char/number(param1) , char/number(param2) )

if number = 1

return param1

else param 2

similar to oracle decode, but I dont know how to do, do you have any ideia? Maybe clr function but I think overload function via c# doesn't work as well

thanks,

|||

Hi Alessandro,

I think I understand what you want, and the below will let you do this:

create function fntest2 (@.one sql_variant, @.two sql_variant)
returns sql_variant
as
begin
declare @.ret sql_variant

set @.ret = 0

if (select SQL_VARIANT_PROPERTY(@.one,'BaseType')) = 'int'
begin
set @.ret = @.one
end
else
begin
set @.ret = @.two
end

return (@.ret)
end;

Is that what you were after, or did you mean something else?

Cheers,
Rob

|||

Hi Rob,

Yes, but when you call with float from Select clauses like

select fntest( 1 , value1(float) , value2 (float) )

doesn't work I need to convert, have you tried?

Thanks

|||

Hi Alessandro,

What about the below:

create function fntest2 (@.one int, @.two sql_variant, @.three sql_variant)
returns sql_variant
as
begin
declare @.ret sql_variant

set @.ret = 0

if (select SQL_VARIANT_PROPERTY(@.two,'BaseType')) = 'int'
begin
set @.ret = 'it is an int'
end
else if (select SQL_VARIANT_PROPERTY(@.two,'BaseType')) = 'float'
begin
set @.ret = 'it is a float'
end
--more if else statements here...

return (@.ret)
end;

declare @.f float
set @.f = 123.9982

select tempdb.dbo.fntest2( 1 , @.f , 'another param here' )

This returns the character line "it is a float" as the param @.f is explicity defined as float. If you execute the below line:

select tempdb.dbo.fntest2( 1 , 23.55 , 'another param here' )

0 will be returned as 23.55 is interpreted as type numeric

Cheers,

Rob

|||

Hi Rob,

Woks well, thanks, however when I try doing this

select tempdb.dbo.fntest2( 1 , 23.55 , 'another param here' ) - tempdb.dbo.fntest2( 1 , 23.55 , 'another param here' )

I receive this msg

Operand data type sql_variant is invalid for subtract operator.

thanks,

|||

Hi Alessandro,

Yes, that's correct - you cannot perform mathematical operations on the sql_variant datatype. This makes sense as sql has no idea what type it is: it may be binary, or one may be char, and the other numeric or both may be char, in which case you would receive concatenation of the two char values: probably not what you intended...

You'll need to perform an explicit cast as such:

declare @.a sql_variant,
@.b sql_variant

set @.a = 2;
set @.b = 1;

begin try
select (cast(@.a as int) + cast(@.b as int)) as 'sum'
end try
begin catch
print ERROR_MESSAGE()
end catch

You'll need to include the explicit cast in a try block in order to catch any conversion errors (for example, if @.a is a char value, not int).

Cheers,

Rob