applumap()

[#1]

Hi to All,

why we go for apply map() instead of join, why apply map() why not join.

what is the difference b/w those.

Thanks in advance

Reagrsd

chandra.

[tresesco]

Read this blog : Don't join - use Applymap instead

[jonathandienst]

ApplyMap is a simple lookup and operates a lot like vlookup() in Excel. You will never impact the number of rows on that loaded table and it is part of a single load step, but it can only add a single column to the output. It is usually very fast.

Join can impact the number of rows in the output, and requires an extra load step as well as the join logic, which may require a lot of RAM and take a long time if the data set is large, but a join can add multiple columns at once.

HTH

Jonathan

[aapurva09]

Hi,

Join: It will join 2 table on the basis of common field values in keys of 2 different tables but it can not flag mismatch field values in those keys.

Applymap() is used to find data match and mismatch. It matches the common field values from both the keys of different tables and also able to flag the mismatched field values.

Thanks,

Apurva

[rajkumarb]

HI

Please Check this Link

http://www.quickintelligence.co.uk/applymap-is-it-so-wrong/