On Sun, Nov 2, 2014 at 3:40 PM, rohtodeveloper <rohtodevelo...@outlook.com> wrote:
> > Dear > > > In 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
