Skip to content
Advertisement

Tag: row-number

Temp sequence in postgres view

I have a table that I order a certain way often. That ordering is the basis of a derived column we can call rank. If I query the entire table, I can have the database calculate that rank for me: This yields useful results like: With that result set I can determine the rank of any foo. However this requires

how to avoid duplicate on Joining two tables

This result is 2 times A even after using disticnt . My expected result will have only one A. if i remove row_number() over() as rownum its working fine. Why this is happening ? how to resolve. AM using DB2!! Answer There are two rows in marks Table with id = 1 and mark = 50.. So you will get

Should SQL ranking functionality be considered as “use with caution”

This question originates from a discussion on whether to use SQL ranking functionality or not in a particular case. Any common RDBMS includes some ranking functionality, i.e. its query language has elements like TOP n … ORDER BY key, ROW_NUMBER() OVER (ORDER BY key), or ORDER BY key LIMIT n (overview). They do a great job in increasing performance if

Advertisement