Applymap,Join,Keep

[venkey2847]

Hi All,

In which situations we will go for Apply map(),join,keep?

I know like if we have two fields in a table then will go for apply map(), if we do use Left Join what will happen?why we only go for Apply map()?

if mapping table have duplicate values how it will works?

Performance wise Keep would be fine, how can we decide that would be fine rather than join?

As per my Knowledge

If we have one to one relationship between the rows then will go for Join

one to many and many to many will go for Keep

Please correct me if i am wrong.

Thanks in Advance..

regards

Venkey

[maxgro]

HIC wrote some useful docs on jon, keep, etc....

Don't join - use Applymap instead

To Join or not to Join

Joins and Lookups

You can also find some useful info in the Qlik help

Keep

The keep prefix is similar to the Join prefix. Just as the join prefix, it compares the loaded table with an existing named table or the last previously created data table.

But instead of joining the loaded table with an existing table, it has the effect of reducing one or both of the two tables before they are stored in QlikView, based on the intersection of table data. The comparison made is equivalent to a natural join made over all the common fields, i.e. the same way as in a corresponding join. However, the two tables are not joined and will be kept in QlikView as two separately named tables.

Join

The join prefix joins the loaded table with an existing named table or the last previously created data table. The join is a Natural Join made over all the common Fields. The join prefix may be preceded by one of the prefixes Inner, Outer, Left or Right.

Or in these 2 images