Changing query based on record value-CodePudding

So I have this table to see usage report, Let's say column A B C D E F

if column F has a particular value I want to A B C = E else I wanted A B C D = E

My brain can't handle the logic to be it in SQL query Do I need to use IF ELSE or DECLARE or CAST or idk

CodePudding user response：

Here is a possible way to do this; anyway I'd suggest to have a look to the SELECT CASE documentation since it's not that complicated (I assumed you're using sql server):

SELECT CASE F 
WHEN 'a particular value' THEN A   B   C 
WHEN 'not a particular value' THEN A   B   C   D
END AS E
FROM YourTable

Edit: as suggested by @JonasMetzler, an ELSE would also do the job:

SELECT CASE F 
WHEN 'a particular value' THEN A   B   C 
ELSE A   B   C   D
END AS E
FROM YourTable

And since there seem to be just 2 options for F value to evaluate ('being a certain value' and 'not being it'), we could also use an IIF statement:

SELECT IIF(F = 'a certain value', A   B   C, A   B   C   D) AS E 
FROM YourTable

and in the three examples, you could extract the A B C part since they are always added:

SELECT IIF(F = 'a certain value', 0, D)   A   B   C AS E 
FROM YourTable