I am a beginner concerning the Teradata. I was trying to find simple descriptions on the internet about functions QUALIFY; RANK; OVER; PARTITION BY - unfortunately unsuccessfully. I coudn't find a simple explanation what does each of the funcions do.
Can anyone send me a link or give a explanation about this functions.
Here is the part of the SQL I'm trying to figure out:
RANK basically assigns a sequential numeric identifier to each row depending on the criteria mentioned in OVER(...) clause
OVER defines the criteria based on which the sequential numbers are assigned
PARTITION BY defines the partitioning scheme, whenever there is a change of values in the paritioning scheme the sequential identifier is reset.
QUALIFY limits the number of records
You can find much more details on this link;
thew document http://www.teradataforum.com/teradata_pdf/b035-110
You don't want this document :-)
It's a a link to an old V2R5 Teradata manual, you'll find the latest version at www.info.teradata.com:
SQL Function, Operators ...