SQL query example describing COUNT function and GROUP BY

Question: Write a query on the TRANSACTIONS DB2 table that lists the number of orders (ORDER_ID) assigned to a specific transaction (TRANSACTION_ID).

Solution

We can use the following query to find the order quantity assigned to a specific transaction ID on the TRANSACTIONS DB2 table.

Example

SELECT TRANSACTION_ID, COUNT(ORDER_ID) FROM TRANSACTIONS
   GROUP BY TRANSACTION_ID

We will use GROUP BY function on ORDER_ID to get the results in order. The COUNT function will count the order quantity. For example, we have the following DB2 ORDERS table.

IRN22345A23118##IRN22345IRN22345 IRN56902##IRN99781IRN56902## Results Our DB2 query will return the following results.

TRANSACTION_ID	##ORDER_ID
A45901
A67990
A23119
p> A67921
A23167

TRANSACTION_ID32##1

##COUNT(ORDER_ID)	IRN22345
	##IRN56902
	IRN99781

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