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Alessio
Contributor
Contributor

How to test if a field has value or is null (not linked)?

test.png

Hi,

I have this problem.

I have table A with field 'CodiceArticolo' and table B with fields 'CodiceArticolo' and 'Articolo'.

In a visualization of table type (see image), I have do check if 'Articolo' has no value. I tried to use IsNull function but I noticed that it works only if record in table B exists, while if a record linked to that CodiceArticolo doesn't exist in table B (and so I have no value for 'Articolo') IsNull function returns a kind of null value.

How can I do? Does other specific function exist?

Thanks

7 Replies
Gabriel
Partner - Specialist III
Partner - Specialist III

Hi,

Try IF(ISNULL(Articolo) OR LEN(Articolo) =0,'T','F')

Anil_Babu_Samineni

FIFO :  Try this?

IF(Len(Articolo)>0, 'F', 'T')

Best Anil, When applicable please mark the correct/appropriate replies as "solution" (you can mark up to 3 "solutions". Please LIKE threads if the provided solution is helpful
Alessio
Contributor
Contributor
Author

Thanks but it doesn't work... none of 2 suggestions

Anil_Babu_Samineni

Should work, For my case with sample it is working

Table1:
LOAD * Inline [
Name
A
B
C
D
];

Table2:
LOAD * Inline [
Name, Name1
A,
B, Sample
C, Sample1
D,
];

 

How is your data looks like?

Best Anil, When applicable please mark the correct/appropriate replies as "solution" (you can mark up to 3 "solutions". Please LIKE threads if the provided solution is helpful
Gabriel
Partner - Specialist III
Partner - Specialist III

Hi,

In the script use script below before table A & B

Map_NullValues:

MAPPING LOAD

NULL()                          AS [MapFrom],

'<Unknown>'           AS [MapTo]

AUTOGENERATE (0);

MAP * USING Map_NullValues;

Then in the UI you can then rewrite your expression IF(FieldName = '<Unknown>', 'T','F')

Alessio
Contributor
Contributor
Author

My data look like this:


Table1:
LOAD * Inline [
Name
A
B
C
D
];

Table2:
LOAD * Inline [
Name, Name1
A,
B, Sample
];
micheledenardi
Specialist II
Specialist II

 

MapValues:
Mapping
LOAD 
	Name,
	Name1
Inline [
Name, Name1
A,
B, Sample
];


Table1:
load
	Name,
	Name1,
	if(isnull(Name1) or trim(Name1)='','True','False') as Flag_IsNull;
LOAD 
	Name,
 	ApplyMap('MapValues',Name,null()) as Name1
Inline [
Name
A
B
C
D
];

 And the result is:

2018-12-10 11_51_26-QlikView x64 - Copia del rivenditore - [C__Users_denardm1_Downloads_test.qvw_].png

Michele De Nardi
If a post helps to resolve your issue, please accept it as a Solution.