InterSystems FAQ rubric
In SQL, NULL data and the empty string ('') are different data. The method for setting and checking each is as follows.
(1) NULL data
[SQL]
insertintotest(a) values(NULL)
select * fromtestwhere a ISNULL[InterSystems ObjectScript]
setx=##class(User.test).%New()
setx.a=""(2) Empty string ('')
[SQL]
insertintotest(a) values('')
select * fromtestwhere a = ''[InterSystems ObjectScript]
setx=##class(User.test).%New()
setx.a=$C(0)For more information, please refer to the following documents:


