Use SELECT Query In Fast Formula

SQL can be used in fast formula with help of TABLE type value set

Steps:

1) Go to Setup and Maintenance >> Search Manage Value Sets for Global Human Resource task >> Create a new value Set
>> Validation Type = TABLE

Module                       -  Module Name  ( Extract etc)
From Clause               -  TABLE Name ( cmp_salary)
Value Column Name  -  ColumnName ( Salary_amount )
WHERE Clause          - Conditions

2) Use Parameter in WHERE Clause if required. ( Parameter will be passed from fast Formula only).
Example
Assignment_id = :{PARAMETER.ASSIGNMENT_ID}

ASSIGNMENT_ID is parameter Name, which need to be passed from Fast Formula.

3) Create Fast Formula and fetch value set value using following method  GET_VALUE_SET('ValueSetName','BindVariable')

ValueSetName - Mandatory - Pass ValueSet Name
BindVariable   - Optional  -  Value for Parameters

Syntex for Bind variable -
'|=PARAMNAME1='''''||Value1||'|PARAMNAME2=''''||Value2||''''


** This method might work only for payroll flow. I could not get return while using from Extract