SQL> select + 'x' from dual;

+
-
x

5 thoughts on “How much is + ‘x’ ?”

1. Jeffrey Kemp April 12, 2012 at 03:55

   Very interesting. Obviously the parser is ignoring the + operator in this instance.

   select dump(0) zero, dump(+’x') plus_x, dump(‘x’) x, dump(+’0′) plus_zero_char, dump(+0) plus_zero from dual;

   ZERO PLUS_X X PLUS_ZERO_CHAR PLUS_ZERO
   —————- —————– —————– —————- —————-
   Typ=2 Len=1: 128
   Typ=96 Len=1: 120
   Typ=96 Len=1: 120
   Typ=96 Len=1: 48
   Typ=2 Len=1: 128

   Unfortunately SELECT – ‘x’ FROM DUAL; doesn’t work so we may never know what a negative character would be.
2. Sokrates April 14, 2012 at 22:53

   works also for date, timestamp and interval – literals:
   

   
   sokrates@11.2 > select +date'2012-04-14', +timestamp'2012-04-14 22:48:00', +interval '1' year from dual;
   
   +DATE'2012-04-14'   +TIMESTAMP'2012-04-1422:48:00'      +INTERVAL'1'YEAR
   ------------------- ----------------------------------- -----------------
   14.04.2012 00:00:00 14-APR-12 10.48.00.000000000 PM     +01-00
   

   
   doesn’t seem to be documented though
3. Laurent Schneider Post authorApril 15, 2012 at 11:00

   while this works :
   

   
   select (-1)* ( interval '1' year ) from dual;
   -01-00
   

   why shouldn’t this work ?
   

   
   select - interval '1' year from dual;
     ORA-00932: inconsistent datatypes: expected NUMBER got INTERVAL YEAR TO MONTH
   

   
   if Oracle knows that +x=x, it should also know that -x=(-1)*x, right?
4. Gary Pennington July 11, 2012 at 17:11

   I would think parser bug, probably stripping optional leading unary + for numerics. Also ‘works’ on columns and ( ).

   SQL> SELECT +(+(+’z'))||+dummy FROM dual;

   +(
   –
   zX
5. Laurent Schneider Post authorJuly 11, 2012 at 18:29

   nice !!!