Misleading Error Message

Hi all. Was working tonight and ran into the following error. Doing a
union between two selects (to get around the lack of outer joins - hint
hint), I was getting the error:

ERROR: Each UNION clause must have the same number of columns

Upon examining the SQL statement in question, I verified that it did,
indeed, have the same number of columns. After some fiddling, I found the
actual problem was that I was doing an ORDER BY on a column which was not
being included in the two select statements. Unfortunately, the error
message wasn't pointing at that.

I'm not sure if this is just a simple change or implies other problems
with the parser but I thought I'd toss it out onto the pile.

Tom Lane discovered it a few days ago in relation to INSERT INTO table
SELECT * FROM TABLE ORDER BY col1, and col1 was not in the select target
list. It shows an error. We are looking at solutions.

-- 
  Bruce Momjian                        |  http://www.op.net/~candle
  maillist@candle.pha.pa.us            |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Hi all. Was working tonight and ran into the following error. Doing a
union between two selects (to get around the lack of outer joins - hint
hint), I was getting the error:

ERROR: Each UNION clause must have the same number of columns

Upon examining the SQL statement in question, I verified that it did,
indeed, have the same number of columns. After some fiddling, I found the
actual problem was that I was doing an ORDER BY on a column which was not
being included in the two select statements. Unfortunately, the error
message wasn't pointing at that.

I'm not sure if this is just a simple change or implies other problems
with the parser but I thought I'd toss it out onto the pile.

Tom Lane discovered it a few days ago in relation to INSERT INTO table
SELECT * FROM TABLE ORDER BY col1, and col1 was not in the select target
list. It shows an error. We are looking at solutions.

This might also interfere with latest changes I did in the
rewrite system. Parser and rewriter now add junk attributes
to the targetlist. I think the problem is that the union
code (where the check is done) doesn't recognize that the
unequal length of the targetlists is due to junk attributes.

Jan

--

#======================================================================#
# It's easier to get forgiveness for being wrong than for being right. #
# Let's break this rule - forgive me. #
#======================================== jwieck@debis.com (Jan Wieck) #

Hi all. Was working tonight and ran into the following error. Doing a
union between two selects (to get around the lack of outer joins - hint
hint), I was getting the error:

ERROR: Each UNION clause must have the same number of columns

Upon examining the SQL statement in question, I verified that it did,
indeed, have the same number of columns. After some fiddling, I found the
actual problem was that I was doing an ORDER BY on a column which was not
being included in the two select statements. Unfortunately, the error
message wasn't pointing at that.

I'm not sure if this is just a simple change or implies other problems
with the parser but I thought I'd toss it out onto the pile.

Tom Lane discovered it a few days ago in relation to INSERT INTO table
SELECT * FROM TABLE ORDER BY col1, and col1 was not in the select target
list. It shows an error. We are looking at solutions.

This might also interfere with latest changes I did in the
rewrite system. Parser and rewriter now add junk attributes
to the targetlist. I think the problem is that the union
code (where the check is done) doesn't recognize that the
unequal length of the targetlists is due to junk attributes.

I have added code to the parser and rewrite checks to skip counting of
resjunk nodes in checking for UNION length equality. This should fix
the problem.

-- 
  Bruce Momjian                        |  http://www.op.net/~candle
  maillist@candle.pha.pa.us            |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Hi all. Was working tonight and ran into the following error. Doing a
union between two selects (to get around the lack of outer joins - hint
hint), I was getting the error:

ERROR: Each UNION clause must have the same number of columns

Upon examining the SQL statement in question, I verified that it did,
indeed, have the same number of columns. After some fiddling, I found the
actual problem was that I was doing an ORDER BY on a column which was not
being included in the two select statements. Unfortunately, the error
message wasn't pointing at that.

I'm not sure if this is just a simple change or implies other problems
with the parser but I thought I'd toss it out onto the pile.

This now fixed.

-- 
  Bruce Momjian                        |  http://www.op.net/~candle
  maillist@candle.pha.pa.us            |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026