SQL has many built-in functions for performing processing on string or numeric data. Following is the list of all useful SQL built-in functions:

• SQL COUNT Function - The SQL COUNT aggregate function is used to count the number of rows in a database table.
• SQL MAX Function - The SQL MAX aggregate function allows us to select the highest (maximum) value for a certain column.
• SQL MIN Function - The SQL MIN aggregate function allows us to select the lowest (minimum) value for a certain column.
• SQL AVG Function - The SQL AVG aggregate function selects the average value for certain table column.
• SQL SUM Function - The SQL SUM aggregate function allows selecting the total for a numeric column.
• SQL SQRT Functions - This is used to generate a square root of a given number.
• SQL RAND Function - This is used to generate a random number using SQL command.
• SQL CONCAT Function - This is used to concatenate any string inside any SQL command.
• SQL Numeric Functions - Complete list of SQL functions required to manipulate numbers in SQL.
• SQL String Functions - Complete list of SQL functions required to manipulate strings in SQL.