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hic
Former Employee
Former Employee

One of the strengths of QlikView is its search engine. With it, you can find pieces of information in a fraction of a second and select the found field values. But how is the search defined? And where can the search be used?

Obviously, a search is defined by the search string that you enter when you search for something. But there are several different ways a search string can be interpreted. See for instance the picture below: In the normal search to the left you have a different result set from what you get in the wildcard search.

 

search h.png

 

The logic is the following:

 

  • Normal search
    The search string is matched against the beginning of every word in the field value. Normal search is used only in interactive searches.
  • Wildcard search
    If the search string contains a wild card or the search string is used in a programmatic search (e.g. in a Set Analysis expression), a wildcard search is made instead of a normal search. This means a strict, case insensitive, match between the search string and the field values, where the only way of representing unknown characters is explicit use of wild cards.
  • Numeric search
    If the search string begins with ‘<’ or ‘>’, a numeric comparison is made. E.g. ‘>=1000’. Only values that fulfill the numeric requirement will be matched.
  • Expression search
    If the search string begins with an equals sign ‘=’, an expression search is made. E.g. ‘=Sum(Sales)>1000’. Then an aggregation is made for each value in the field, and a match is found if the expression is true. This means that you can make a selection in one field based on an aggregation in another field.
  • Fuzzy search
    If the search string begins with ‘~’, a fuzzy search is made. This means that all field values are ranked according to similarity and the top one will be selected when you hit return.
  • Compound search
    Using a compound search, you can express more complicated search conditions with logical operators. Use brackets and ‘&’ or ‘|’, e.g. ‘(California|Nevada)’.

 

search num.png

 

Hence, how the search string is interpreted depends only on which characters it contains. The settings in the list box properties do not affect the evaluation. The "Default Search Mode" only affects how the initial search string is created.

 

Further, you can use the search string in a number of different places, not just in the search area in the user interface: You can also use it in Set analysis, in actions, in bookmarks, in API calls, etc.

 

In principle, you can combine any search string with any search place. There are however some anomalies and exceptions. For example, you cannot use normal search or fuzzy search in programmatic searches and you cannot use the advanced search modes in the Qlik Sense global search.

 

Type and place2.png

 

The bookmark deserves a special mention. If a search is made and the resulting selection is stored in a bookmark, the bookmark remembers the search string and not the selection. This means that if new values appear when the script is run, they may be selected by the bookmark, even though they didn’t exist when the bookmark was created.

 

HIC

 

Further reading related to this topic:

Text searches

Search - But what shall you find?

The Expression Search

63 Comments
Not applicable

Informative.

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sibideepak
Creator II
Creator II

Very useful post .. Thank you

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Not applicable

Thanks for the post.  Indeed I have a question about using the Expression Search and bookmark it.

If I added two bookmarks, 1. avg(reading1) > 1.05 or avg(reading1)<0.95

and 2. avg(reading2) > avg(reading2)+2*stdev(reading2)

As in bookmark help page, it said it will CLEAR all selections before applying the bookmark, unless you check on the "+" column in manage bookmark dialog.

However, it seems that the clear action is not done, i.e. I applied bookmark 1, and it selected 3 values.

Then I applied bookmark2, it will not select another 4 values that I expect, but instead just clear my selection unless I applied it again (of course).  Is it WAD?

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hic
Former Employee
Former Employee

In an expression search the search string is evaluated given the current selection, so in your case it returns an empty result set, and no selection is made. Instead it clears the old selection.

If you instead try

   =Avg({1} reading1) > 1.05

you will search all values and probably get what you want.

The background is that an expression search is an aggregation, which means that a hypercube is created, in the same way as when you have a chart. This is different from a numeric search or a wildcard search where the symbol tables are used instead.

So, I'd say it's a WACD - Works As Correctly Designed.

HIC

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m_woolf
Master II
Master II

Henric,

There appears to be a 1024 character limit to the search string. Do you know any way to increase that limit?

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hic
Former Employee
Former Employee

Didn't know that that existed... I just tested it and, indeed there is such a limit on the input control of the list box in the desktop client. And no, there is no way to change this.

But there is no such limit on the search string itself. Longer search strings work fine in Set Analysis expressions and in Ajax list boxes.

HIC

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Not applicable

Henric,

Will be possible to implement levenshtein distance kind of thing with Qlik? I try it and i can achieve it with the power of Macro. Other than macro, is there any possibility? Levenshtein Distance is very similar to fuzzy search. Thats why i come up with such a question.

Thanks,

Omer

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2908nmadao
Contributor III
Contributor III

Good morning Henric Cronström !

I have an issue with the search field or more of an enhancement that I would like to do to my application.

I have my tables qualified and when I perform a search, it shows the name of the table and does not look great. Is there a way to rename the fields when they appear in the search box?

Could you please let me know if this is possible?

Thanks in advance.

Kind regards,

Nelson.

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blaise
Partner - Specialist
Partner - Specialist

Hi Nelson

Sadly not possible, and this is one of my most requested / wanted feature, one fieldname for GUI/end-user and another fieldname for Datamodeling/Developer.

Qlik Sense helps a bit as you can declare meassures and dimension in your library - hope to this this in next version of QlikView.

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2908nmadao
Contributor III
Contributor III

Thanks Johan Hessler!

This is a shame. I thought it would be possible to mask the field or maybe there is a workaround that someone found and hasn't shared yet?

Thank you very much!

Kind regards

Nelson

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