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jblomqvist
Contributor II

What is the danger of putting 'MISSING' (String value) in Numeric, Date type fields, if any?

Hello all,

What is the danger of putting 'MISSING' (String value) in Numeric, Date type fields, if any?

I can see that we are mixing a string value with different formats but how would that impact some Qlik calculations?

E.g. If you were to create a Line Graph or Count on some numeric data, what would be the impact?

5 Replies

Re: What is the danger of putting 'MISSING' (String value) in Numeric, Date type fields, if any?

Never tried it and to be honest I never would as it sounds fraught with risks.

The question I would ask is why do you wish to do this ?

arvind_patil
Valued Contributor III

Re: What is the danger of putting 'MISSING' (String value) in Numeric, Date type fields, if any?

Hi John,

It will not affect on anywhere.

Thanks,

Arvind Patil

jblomqvist
Contributor II

Re: What is the danger of putting 'MISSING' (String value) in Numeric, Date type fields, if any?

Hi Bill,

I thought the same.

My suggestion was to analyse the data first to identify fields which would be used and if there are null values.

The issue my company sees is that they cannot select on null values in some fields (e.g. in filter pane) and because they cannot see the null values there as a default, they cannot see this as an issue until it is identified as an issue.

So they were looking to use something default like MISSING for all the fields in a data model.

I can see their point but at the same time I wonder what this would do to date or numeric fields, and I am seeing what someone experienced here has to say about this.

Re: What is the danger of putting 'MISSING' (String value) in Numeric, Date type fields, if any?

I wouldn't use 'MISSING' or 'NULL' or something similar within measure-fields. Within dimension-fields instead it might be useful because you make the unselectable NULL to a selectable real-value. If you really need this you won't need to worry about the effects on RAM consumption or performance because you need it and which are probably too small to notice them (of course there will be some exceptions, for example by fields with a large amount of distinct and consecutive field-values which are normally handled like an autonumber-field and an added string would break that).

- Marcus

Re: What is the danger of putting 'MISSING' (String value) in Numeric, Date type fields, if any?

Maybe in the load script create another flag field derived from measure field the called say Measure is Null with a simple value of Yes or No which would be a Dimension.  Then you could create a filter on this flag and maybe an extra viz for Data Quality.

Data Quality in real life data is oft not perfect and in some dashboards I create dedicated Data Quality sheet so the Users can easily see the wart's 'n all.  This often encourages people to make sure the source data is better quality, especially when those higher up the food chain can easily see and count the warts.

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