Difference between SCALAR and COLUMN function

The DB2 SCALAR functions take a single column value and returns a single result. The COLUMN function takes the column value from multiple rows of a DB2 table and returns a single result. In case of SCALAR function only one row is involved.

For example, if we have an ORDERS DB2 table and we want to return only the integer value of the ORDER_TOTAL for all the orders placed on 15-08-2020. We will use the below query.

Example

SELECT ORDER_ID, INTEGER(ORDER_TOTAL) FROM ORDERS
   WHERE ORDER_DATE = ‘15-08-2020’

In this case, if any ORDER_ID Z55641 is having the ORDER_TOTAL as 3422.89, then we will get the following result.