What is the string concatenation operator in Oracle SQL?
Are there any "interesting" features I should be careful of?
(This seems obvious, but I couldn't find a previous question asking it).
+7
A:
It is ||, for example:
select 'Mr ' || ename from emp;
The only "interesting" feature I can think of is that 'x' || null returns 'x', not null as you might perhaps expect.
Tony Andrews
2008-11-10 15:45:06
I'd expect null from a logical operation... not sure I'd ever thought about a string operation.
2008-11-10 15:48:00
Well of course Oracle treats null and '' as the same, and 'x' || '' = 'x' makes sense. But if you think of null as "undefined" or "unknown" then 'x' || null could be any string beginning with 'x' and so is itself "unknown"!
Tony Andrews
2008-11-10 16:02:15
A:
There's also concat, but it doesn't get used much
select concat('a','b') from dual;
Gary
2008-11-10 22:09:11