Explain SQL describing COUNT aggregate and CURRENT DATE function

Problem: Write a SQL query to count the number of orders which were placed today from the ORDERS DB2 table. (The date should not be hardcoded)

Solution

We can find the count of orders which are placed today using the below DB2 query:

Example

SELECT COUNT(ORDER_ID) AS ORDER_COUNT FROM ORDERS
WHERE ORDER_DATE = CURRENT DATE

In this query, we have used the COUNT COLUMN function which will count the total number of ORDER_ID (primary key). In the WHERE clause, we will use the predicate for the ORDER_DATE column. The CURRENT DATE is a DB2 inbuilt function which will return the current system date.

For example, if we have below ORDERS DB2 table:

ORDER_ID	ORDER_TOTAL	ORDER_DATE
Z22345	342	28-07-2020
Z62998	543	30-07-2020
Z56990	431	28-07-2020
Z56902	6743	29-07-2020
Z99781	443	27-07-2020
Z56112	889	30-07-2020

 

If the current date is 30-07-2020, then the query with CURRENT DATE predicate will return the below result:

ORDER_COUNT

2