Aggregate and Scalar functions are in built function for counting and calculations.
Aggregate functions operate against a group of values but returns only one value.
- AVG(column) :- Returns the average value of a column
- COUNT(column) :- Returns the number of rows (without a NULL value) of a column
- COUNT(*) :- Returns the number of selected rows
- MAX(column) :- Returns the highest value of a column
- MIN(column) :- Returns the lowest value of a column
Scalar functions operate against a single value and return value on basis of the single value.
- UCASE(c) :- Converts a field to upper case
- LCASE(c) :- Converts a field to lower case
- MID(c,start[,end]) :- Extract characters from a text field
- LEN(c) :- Returns the length of a text