|TechTip: Use Interactive SQL from the IBM i Command Line|
|Tips & Techniques - SQL|
|Written by Thomas Snyder|
|Thursday, 19 March 2009 20:00|
SQL is a very powerful and flexible language. This article introduces the interactive SQL command line tool to run SQL statements on your IBM i.
By Tom Snyder
In this TechTip, we'll explore the functionality of the interactive SQL tool.
Library Lists and File Overrides
The SQL statements that you run from the command line use the library list of the session that you are signed onto; therefore, you can refer to the physical files by name and they will have the same reference as your F-specs. When you are initially trying out interactive SQL, I recommend that you copy a file into a test library and put that library on the top of your library list.
If you are working with a multiple-member file, you can execute an OVRDBF command at the command line before you call the STRSQL command. Before you execute any queries using the interactive SQL tool, I recommend that you execute an OVRDBF command for the file you will be working with and then DBU the file without a library or member reference to make sure you're working with the correct file and to double-check your overrides and library list.
OK, you have your test environment established and you're ready to go.
SQL Practical Example
For a practical example, let's suppose your accounting department set up a new product on the system with the correct code of 777, but the incorrect category of "Columbian." Some billing has already been performed, and the reports are showing the revenue in the wrong category. They have since corrected the code attributes, but the history still reflects the wrong code. (I know this never happens, but it's just for example purposes.)
You could write a program to do this, or you could do this more quickly by using interactive SQL.
Suppose you have the following simple BILLING file:
For this example, you want to create a SELECT query to review the records that will be affected by the update. You can initially review the results of the report to tweak your SQL statement until you get the desired results. You could also present this report to the person who identified the problem to ensure that the correct records are being identified for update.
To view all of fields for all of the records in the BILLING file:
SELECT * FROM BILLING
To view only records of interest:
SELECT * FROM BILLING WHERE BCODE = 777 AND BCAT = 'Columbian'
The SELECT query for the records of interest will provide the following results:
|Last Updated on Thursday, 19 March 2009 12:32|