Re: How to implent CONVERT ( data_type [ ( length ) ] , expression ) function in postgreSQL
| От | rohtodeveloper |
|---|---|
| Тема | Re: How to implent CONVERT ( data_type [ ( length ) ] , expression ) function in postgreSQL |
| Дата | |
| Msg-id | BAY178-W181CE2A53835F8345B488EC4980@phx.gbl обсуждение исходный текст |
| Ответ на | Re: How to implent CONVERT ( data_type [ ( length ) ] , expression ) function in postgreSQL (Atri Sharma <atri.jiit@gmail.com>) |
| Ответы |
Re: How to implent CONVERT ( data_type [ ( length ) ] ,
expression ) function in postgreSQL
Re: How to implent CONVERT ( data_type [ ( length ) ] , expression ) function in postgreSQL |
| Список | pgsql-hackers |
I need the convert function because that Our application will be switched from SQL Server to PostgreSQL.
Date: Sun, 2 Nov 2014 16:00:14 +05
Subject: Re: [HACKERS] How to implent CONVERT ( data_type [ ( length ) ] , expression ) function in postgreSQL
From: atri.jiit@gmail.com
To: rohtodeveloper@outlook.com
CC: pgsql-hackers@postgresql.org
>For the options you suggested:
>1) Pass in datatype as string and deparse and process in the function.
>2) Are you referring to pg_convert here?
1) is yes. but I want to use the CONVERT ( data_type [ ( length ) ] , expression ) just as same as in the SQLServer, SO, that doesn't work.
2) I mean modifying the 'src\backend\parser\gram.y' file. There will be a grammer conflict with the PostgreSQL self's convert(data,src_encoding_name,dest_encoding_name) function.
Date: Sun, 2 Nov 2014 16:00:14 +05
Subject: Re: [HACKERS] How to implent CONVERT ( data_type [ ( length ) ] , expression ) function in postgreSQL
From: atri.jiit@gmail.com
To: rohtodeveloper@outlook.com
CC: pgsql-hackers@postgresql.org
On Sun, Nov 2, 2014 at 3:40 PM, rohtodeveloper <rohtodeveloper@outlook.com> wrote:
DearIn SQLServer, there'are two functions to converte an expression of one data type to another.1. CAST ( expression AS data_type [ ( length ) ] )2. CONVERT ( data_type [ ( length ) ] , expression )However, In PostgreSQL, there's only the CAST ( expression AS data_type [ ( length ) ] ) function. I have tried the following two ways to implenting the CONVERT ( data_type [ ( length ) ] , expression ) function, but both are failed.1. CREATE FUNCTION .....The function's arguments can only be expressions but not data_type .2. Modifying the gram.y .....The CONVERT ( data_type [ ( length ) ] , expression ) is in grammer conflict with the PostgreSQL self's convert(data,src_encoding_name,dest_encoding_name) function. And the PostgreSQL self's convert(data,src_encoding_name,dest_encoding_name) function cannot be used.I wonder whether there's a better way to solve this problem.Any help will be appreciated.Please do not cross post to multiple lists.
Please do not cross post to various lists.
For the options you suggested:
1) Pass in datatype as string and deparse and process in the function.
2) Are you referring to pg_convert here?
IMO I do not understand why you need the convert function in the first place. You may want to refer to http://www.postgresql.org/docs/9.3/static/typeconv.html
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