Nsryjdtyk

Please explain how to get the last day of the previous month in SQL Server.

I don't want to use built in function.

Something like this will work in SQL Server 2012 or newer:
(all versions before that are out of mainstream support anyway and should be upgraded)

DECLARE @Today DATE = SYSDATETIME();

DECLARE @Year INT = YEAR(@Today);

DECLARE @Month INT = MONTH(@Today);



DECLARE @FirstOfMonth DATE = DATEFROMPARTS(@Year, @Month, 1);



DECLARE @LastOfPreviousMonth DATE = DATEADD(DAY, -1, @FirstOfMonth);



SELECT @LastOfPreviousMonth;

but of course, this uses a lot of built-in functions - so why exactly don't you want to use any built-in functions?!??!?!

I have no idea what you mean by without built in functions; as you have to use them. A couple of methods though:

DATEADD(DAY,-1,DATEADD(MONTH,DATEDIFF(MONTH,0,GETDATE()),0))

EOMONTH(DATEADD(MONTH,-1,GETDATE()))

You're not going to be able to achieve this weekend without using at least a couple of functions, and without your explanation as to why, I can see no good reason why you should't be using them.