Drop Down MenusCSS Drop Down MenuPure CSS Dropdown Menu

PostgreSQL 9.4 FILTER CLAUSE

PostgreSQL 9.4 has introduced one of the very good FILTER CLAUSE which is used to apply filters in aggregate functions.
Using FILTER, You can use different types of aggregate functions without applying any GROUP BY CLAUSE.
Now Imagine, that I have one Student table and I want total number of Students based different grades.
What happened without FILTER CLAUSE, We have to perform this calculation in the individual SELECT query.
But with the use of FILTER CLAUSE we can perform aggregation based on different FILTER values in a single SQL Query.
Below is a small demonstration of this:
Create one Student table with sample data:
Apply FILTER clause to count number of Students based on Marks:

Comments

Popular posts from this blog

How to find the server is whether standby (slave) or primary(master) in Postgresql replication ?

spfile and pfile errors

How to Get Table Size, Database Size, Indexes Size, schema Size, Tablespace Size, column Size in PostgreSQL Database

2017 Shortern URL - Other Website Like ADFOC.US

ORA-01261: Parameter db_recovery_file_dest destination string cannot be translated ORA-01262: Stat failed on a file destination directory Linux-x86_64 Error: 2: No such file or directory