Обсуждение: Confused by to_char

I am am trying to get a day string from a date using to_char ie:

SELECT date1,ti1 ,to1,ti2,to2,adj,ei,eo,to_char('2005-02-07','Day') FROM
vw_times_list1

however I get

function to_char("unknown", "unknown") is not unique

(using to_date does not recognise the date format)

anyone any ideas what I am doing wrong

On Tue, 2005-02-08 at 12:28 +0000, mike wrote:
> I am am trying to get a day string from a date using to_char ie:
>
> SELECT date1,ti1 ,to1,ti2,to2,adj,ei,eo,to_char('2005-02-07','Day') FROM
> vw_times_list1
>
> however I get
>
> function to_char("unknown", "unknown") is not unique

test=# select to_char('2005-02-07'::date,'Day');
  to_char
-----------
 Monday
(1 row)


gnari

On Tue, Feb 08, 2005 at 12:28:26PM +0000, mike wrote:
> I am am trying to get a day string from a date using to_char ie:
>
> SELECT date1,ti1 ,to1,ti2,to2,adj,ei,eo,to_char('2005-02-07','Day') FROM
> vw_times_list1
>
> however I get
>
> function to_char("unknown", "unknown") is not unique
>
> (using to_date does not recognise the date format)
>
> anyone any ideas what I am doing wrong
>
Yes, in a way.

to_char needs two parameters, a pattern and a variable to format
according to the pattern.  You've given it a pattern it doesn't
recognise and a constant string which doesn't look like a date.

It needs to look something like:-

    to_char(date_time, 'RRRRMMDDHH24MISS')

This is an Oracle example so I'm not sure if the pattern is exactly
right but it'll look something like this.  Look at the documentation
for to_char() for the format of the pattern.  date_time is a date
column in your database.

--
Chris Green (chris@areti.co.uk)

    "Never ascribe to malice that which can be explained by incompetence."

On Tue, 2005-02-08 at 13:00 +0000, Ragnar Hafstað wrote:
> On Tue, 2005-02-08 at 12:28 +0000, mike wrote:
> > I am am trying to get a day string from a date using to_char ie:
> >
> > SELECT date1,ti1 ,to1,ti2,to2,adj,ei,eo,to_char('2005-02-07','Day') FROM
> > vw_times_list1
> >
> > however I get
> >
> > function to_char("unknown", "unknown") is not unique
>
> test=# select to_char('2005-02-07'::date,'Day');
>   to_char
> -----------
>  Monday
> (1 row)
>
>


thanks for this - I found the solution to my immediate problem by
looking through a dump for to_char and found the function I was looking
for at the moment (dayname) but this will be useful for the general case

Mike
> gnari
>
>
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