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This question comes from my previous post.
I’m curious as to why:
select * from TPM_USER where '' = ''
Returns zero rows, however:
select * from TPM_USER where 1 = 1
Returns every row in the table. Is this per SQL standard, or is this Oracle specific?
Oracle SQL Fiddle.
The following work as expected:
PostgreSQL SQL Fiddle
SQL Server SQL Fiddle
mySQL SQL Fiddle
In Oracle, an empty string equates to NULL. You don’t use
=for NULL values.