Обсуждение: Function in psql to Compare two numbers and return the bigger value

HEllo,

I am looking for a psql method to get the bigger value of two numbers.

For example,

methodName(12.6, 3.8)

Will return 12.6

Thanks!

You want GREATEST()

<http://www.postgresql.org/docs/8.2/interactive/functions-conditional.ht
ml#AEN13140>


-----Original Message-----
From: pgsql-general-owner@postgresql.org
[mailto:pgsql-general-owner@postgresql.org] On Behalf Of Emi Lu
Sent: Tuesday, February 13, 2007 12:37 PM
To: pgsql-general@postgresql.org
Subject: [GENERAL] Function in psql to Compare two numbers and return
the bigger value


HEllo,

I am looking for a psql method to get the bigger value of two numbers.

For example,

methodName(12.6, 3.8)

Will return 12.6

Thanks!

---------------------------(end of broadcast)---------------------------
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Emi Lu wrote:
> HEllo,
>
> I am looking for a psql method to get the bigger value of two numbers.
>
> For example,
>
> methodName(12.6, 3.8)
>
select greatest(12.6,3.8);

>> I am looking for a psql method to get the bigger value of two numbers.
>>
>> For example,
>>
>> methodName(12.6, 3.8)
>>
> select greatest(12.6,3.8);

It does not work for me,
select greatest(12.6,3.8);
ERROR:  function greatest(numeric, numeric) does not exist
HINT:   No function matches the given name and argument types. You may
need to add explicit type casts.

In 8.1 docs, it says that:
GREATEST(value [, ...])
LEAST(value [, ...])

* Note that GREATEST and LEAST are not in the SQL standard, but are a
common extension. *

Does it mean it is not allowed to use "select greatest(12.6,3.8)" ?

thanks

Emi Lu wrote:
>
>>> I am looking for a psql method to get the bigger value of two numbers.
>>>
>>> For example,
>>>
>>> methodName(12.6, 3.8)
>>>
>> select greatest(12.6,3.8);
>
> It does not work for me,
> select greatest(12.6,3.8);
> ERROR:  function greatest(numeric, numeric) does not exist
> HINT:   No function matches the given name and argument types. You may
> need to add explicit type casts.
>
> In 8.1 docs, it says that:
> GREATEST(value [, ...])
> LEAST(value [, ...])
>
> * Note that GREATEST and LEAST are not in the SQL standard, but are a
> common extension. *
>
> Does it mean it is not allowed to use "select greatest(12.6,3.8)" ?

I see the reason, my version is 8.0.8. The doc is for 8.1.

Thank you for all your help!

Emi Lu wrote:
> Does it mean it is not allowed to use "select greatest(12.6,3.8)" ?

It may mean you're not running 8.1?  Here's what I get:
-----------------------------------------------------------
->psql
Welcome to psql 8.1.4, the PostgreSQL interactive terminal.

Type:  \copyright for distribution terms
       \h for help with SQL commands
       \? for help with psql commands
       \g or terminate with semicolon to execute query
       \q to quit

swampler=# select GREATEST(6.3, 2.8);
 greatest
----------
      6.3
(1 row)

swampler=# select greatest(6.3, 2.8);
 greatest
----------
      6.3
(1 row)

swampler=#
-----------------------------------------------------------

--
Steve Wampler -- swampler@noao.edu
The gods that smiled on your birth are now laughing out loud.