Re: select function alias

Howard News <howardnews@xxxxxxxxxxxxx> · Wed, 30 Nov 2016 14:03:28 +0000



    On 30/11/2016 13:42, Timoteo Blanco
      wrote:

    
      Howdy,
        

        I've a series of timestamp columns I'd like to alias in
          select statements. psql indicates my alias doesnt exist after 
        I define it. 
        

        Example -> select
          to_char(impressions_create_date,'yyyy-mm-dd') as ymd from
          impressionsdb where ymd like '2016-11%' ;

        
        psql always complains column ymd does not exist. I've
          inherited a series of tables with many timestamps and would
          like to 
        shorten the select in queries without renaming any columns.
        

        postgresql 9.2 on Gentoo 4.4.26
        

        TIA, TRB
        

    3 options:

    
      Use the same to_char _expression_ in the where clause
      Use a sub-select to use the alias in the outer where clause
      Use the original column in the where clause and use the
        timestamp comparisson functions.
    
    Howard.