topic Re: After a test, 'drop field' can drop several fields, what is really the difference vs 'drop fields'? in QlikView

After a test, 'drop field' can drop several fields, what is really the difference vs 'drop fields'?

julioarriaga — Tue, 29 Aug 2017 17:38:19 GMT

Hi everyone,

I did a test and I stumbled upon that drop field can also drop several fields. So my question is, what is really the difference between the 'drop field' and 'drop fields'?

Thanks.

Re: After a test, 'drop field' can drop several fields, what is really the difference vs 'drop fields'?

rwunderlich — Tue, 29 Aug 2017 17:47:15 GMT

You may spell it "field" or "fields" whether dropping one or many fields.

If you are dropping multiple fields, there is a significant performance difference between using one DROP statement vs multiple DROP statements that drop one field each.

DROP FIELD a,b,c;

is faster than

DROP FIELD a;

DROP FIELD b;

DROP FIELD c;

The reason is that QV rewrites the records array after every DROP statement, which can take a few seconds in a large table. This may be less of an issue in QV12, haven't benchmarked it.

-Rob

http://masterssummit.com

http://qlikviewcookbook.com

Re: After a test, 'drop field' can drop several fields, what is really the difference vs 'drop fields'?

its_anandrjs — Tue, 29 Aug 2017 17:54:23 GMT

You can write also in single statement which is fastest as ROB suggested

DROP FIELDS a,b,c;

Re: After a test, 'drop field' can drop several fields, what is really the difference vs 'drop fields'?

julioarriaga — Tue, 29 Aug 2017 18:03:58 GMT

So basically it is the same with 'drop field' and 'drop fields' when you're dropping several fields?

Re: After a test, 'drop field' can drop several fields, what is really the difference vs 'drop fields'?

rwunderlich — Tue, 29 Aug 2017 18:21:49 GMT

Yes, you can spell it either way and it works exactly the same.

-Rob