Thursday, June 26, 2014

1 + NULL = NULL

If you try to add a null to a number, the result is a null. You can see what I mean in the example below, which I tested in Oracle 10:
 
SQL> select 1 from dual
  2  /
 
         1
----------
         1
 
SQL> select nvl(null,'null') from dual
  2  /
 
NVL(NULL,'NULL')
----------------
null
 
SQL> select nvl(to_char(1+null),'null') from dual
  2  /
 
NVL(TO_CHAR(1+NULL),'NULL')
---------------------------
null
 
SQL>

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