Обсуждение: LIKE with no wildcards problem

When doing a select with a LIKE in the where clause,
I always get 0 rows if I do not use a wildcard [_%].
LIKE should act like = in this case (and the docs say so).
A select without a from correctly returns 't'.
I am using PostgreSQL 7.1.3 on Solaris.
What am I missing?

Thanks,

John Allison
john@joss.ucar.edu


catalog^> create table foo ( bar char(8) )
CREATE

catalog^> insert into foo values ( 'abc' )
INSERT 38413 1

catalog^> insert into foo values ( '2.20' )
INSERT 38414 1

catalog^> select * from foo  bar    
----------abc     2.20    
(2 rows)

catalog^> select * from foo where bar like 'abc'bar 
-----
(0 rows)

catalog^> select * from foo where bar like 'abc%'  bar    
----------abc     
(1 row)

catalog^> select 'abc' like 'abc'?column? 
----------t
(1 row)

John,

> When doing a select with a LIKE in the where clause,
> I always get 0 rows if I do not use a wildcard [_%].
> LIKE should act like = in this case (and the docs say so).
> A select without a from correctly returns 't'.
> I am using PostgreSQL 7.1.3 on Solaris.
> What am I missing?

> catalog^> create table foo ( bar char(8) )
> CREATE
>

You created the column bar as CHAR(8), which means what's actuallybeing stored is "abc     " not "abc".  I think you
wantto use VARCHARinstead.
 

-Josh

On Thursday 28 February 2002 19:54, John J. Allison wrote:
> When doing a select with a LIKE in the where clause,
> I always get 0 rows if I do not use a wildcard [_%].
> LIKE should act like = in this case (and the docs say so).
> A select without a from correctly returns 't'.
> I am using PostgreSQL 7.1.3 on Solaris.
> What am I missing?
>
> Thanks,
>
> John Allison
> john@joss.ucar.edu
>
>
> catalog^> create table foo ( bar char(8) )
> CREATE
>
> catalog^> insert into foo values ( 'abc' )
> INSERT 38413 1
>
> catalog^> insert into foo values ( '2.20' )
> INSERT 38414 1
>
> catalog^> select * from foo
>    bar
> ----------
>  abc
>  2.20
> (2 rows)

How about:

catalog^> SELECT bar, length(bar) from foo;
  bar    | length 
----------+--------abc      |      82.20     |      8
(2 rows)

The CHARACTER type is always padded to the maximum length, viz:

http://www.postgresql.org/idocs/index.php?datatype-character.html


Ian Barwick

On Thu, Feb 28, 2002 at 11:54:02AM -0700, John J. Allison wrote:
> When doing a select with a LIKE in the where clause,
> I always get 0 rows if I do not use a wildcard [_%].
> LIKE should act like = in this case (and the docs say so).
> A select without a from correctly returns 't'.
> I am using PostgreSQL 7.1.3 on Solaris.
> What am I missing?

The whitespace. Your field is of type CHAR(n), which pads all strings
to the defined width. This behavior is required by the standard. Try
using VARCHAR or TEXT instead.

Ross

> 
> Thanks,
> 
> John Allison
> john@joss.ucar.edu
> 
> 
> catalog^> create table foo ( bar char(8) )
> CREATE
> 
> catalog^> insert into foo values ( 'abc' )
> INSERT 38413 1
> 
> catalog^> insert into foo values ( '2.20' )
> INSERT 38414 1
> 
> catalog^> select * from foo
>    bar    
> ----------
>  abc     
>  2.20    
> (2 rows)
> 
> catalog^> select * from foo where bar like 'abc'
>  bar 
> -----
> (0 rows)
> 
> catalog^> select * from foo where bar like 'abc%'
>    bar    
> ----------
>  abc     
> (1 row)
> 
> catalog^> select 'abc' like 'abc'
>  ?column? 
> ----------
>  t
> (1 row)
> 
> 
> 
> ---------------------------(end of broadcast)---------------------------
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