SQL functions and expressions

You can use functions and expressions to control the appearance and values of rows and columns in your result tables. DB2® offers many built-in functions, including aggregate functions and scalar functions.

A built-in function is a function that is supplied with DB2 for z/OS®.

Concatenation of strings
You can concatenate strings by using the CONCAT operator or the CONCAT built-in function.
Calculation of values in one or more columns
You can perform calculations on numeric or datetime data.
Calculation of aggregate values
You can use the SQL aggregate functions to calculate values that are based on entire columns of data. The calculated values are from only the rows that satisfy the WHERE clause and are therefore selected.
Scalar functions
DB2 offers many different scalar functions, including the CHAR, DECIMAL, and NULLIF scalar functions.
Nested functions
Scalar and aggregate functions can be nested in several ways.
User-defined functions
User-defined functions are small programs that you can write to perform an operation. You can use a user-defined function wherever you can use a built-in function.
CASE expressions
You can use a CASE expression to execute SQL expressions in several different ways depending on the value of a search condition.

Parent topic: Accessing DB2 data