Question

I have 300 records in my database and my structure is something like this

State                      values
Queensland                 4554
Queensland                 2343
Queensland                 9890
NSW                        1333

I want to retrieve all the records with state name Queensland and I want to sum all the records with field name values and the sum to be divided with the number of records (count) with state name.

Can anybody help me out with the syntax to achieve this?

I need something the output to be 5595.66 (i.e. (4454+2343+9890)/3)

Answer 1

SELECT State, SUM(values) / (COUNT(*) * 1.0)
FROM   tableName
WHERE  State = 'Queensland'
GROUP  BY State

OR

SELECT State, AVG(values * 1.0)
FROM   tableName
WHERE  State = 'Queensland'
GROUP  BY State

• SQLFiddle Demo

As a sidenote, the columnName values is a Reserved keyword. Escape it by a delimiter depending on the RDBMS you are using. Like (backtick) MySQL, (brackets) SQL Server, etc….