SQL has a lot of built-in functions can be used for counting and calculations.
SQL Aggregate Functions
SQL Aggregate functions calculate the value obtained from the column to return a single value.
Useful Aggregate Functions:
- AVG () - Returns the average
- COUNT () - Returns the number of rows
- Returns the value of the first record - FIRST ()
- LAST () - Returns the value of the last record
- MAX () - Returns the maximum value
- MIN () - Returns the minimum value
- SUM () - Returns the total
SQL Scalar Functions
SQL Scalar functions based on the input value and return a single value.
Useful Scalar Functions:
- UCASE () - a field will be converted to uppercase
- LCASE () - a field will be converted to lowercase
- MID () - extract characters from a text field
- LEN () - Returns the length of a text field
- ROUND () - for a specified number of decimal places a numeric field rounding
- NOW () - Returns the current system date and time
- Display format of a field - FORMAT ()
Note: In the following sections, we will explain in detail the function Aggregate and Scalar Functions.