Re: LIMIT 1 FOR UPDATE or FOR UPDATE LIMIT 1? - Mailing list pgsql-sql

I found this email from April.  It properly points out that our
LIMIT/FOR UPDATE ordering doesn't match MySQL's, and MySQL's looks more
correct, specifically that the FOR UPDATE is after the LIMIT.  Our
grammar is:

       | select_clause sort_clause opt_for_update_clause opt_select_limit

How do we want to deal with this?  I tried allowing both orderings with
the attached patch but got:

    bison -y -d  gram.y
    conflicts:  4 shift/reduce, 5 reduce/reduce

---------------------------------------------------------------------------

Magnus Enbom wrote:
> Hi,
>
> I've just been hit by a small but annoying difference between postgres(7.2)
> and mysql(4.x).
> In postgresql you do:
>
> SELECT * FROM table FOR UPDATE LIMIT 1;
>
> and in mysql you do:
>
> SELECT * FROM table LIMIT 1 FOR UPDATE;
>
> Is it possible for postgres to accept the mysql syntax as well?
> It's not that many databases that implement LIMIT, so it would be nice if the
> ones that do have the same syntax(or can accept each others variants).
>
> -- Magnus
>
> ---------------------------(end of broadcast)---------------------------
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--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
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Index: gram.y
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/parser/gram.y,v
retrieving revision 2.360
diff -c -r2.360 gram.y
*** gram.y    19 Aug 2002 15:08:47 -0000    2.360
--- gram.y    26 Aug 2002 00:29:24 -0000
***************
*** 4114,4123 ****
--- 4114,4135 ----
                                          nth(0, $4), nth(1, $4));
                      $$ = $1;
                  }
+             | select_clause sort_clause opt_select_limit opt_for_update_clause
+                 {
+                     insertSelectOptions((SelectStmt *) $1, $2, $4,
+                                         nth(0, $3), nth(1, $3));
+                     $$ = $1;
+                 }
              | select_clause for_update_clause opt_select_limit
                  {
                      insertSelectOptions((SelectStmt *) $1, NIL, $2,
                                          nth(0, $3), nth(1, $3));
+                     $$ = $1;
+                 }
+             | select_clause opt_select_limit for_update_clause
+                 {
+                     insertSelectOptions((SelectStmt *) $1, NIL, $3,
+                                         nth(0, $2), nth(1, $2));
                      $$ = $1;
                  }
              | select_clause select_limit