Re: psql variables in the DO command

Pavel Luzanov <p.luzanov@xxxxxxxxxxxxxx> · Mon, 5 Mar 2018 17:22:02 +0300



    Another possible, but inconvenient workaround -
    constructing the right string before execution:

    
    postgres=# \set var 'Hello, World!'

    postgres=# \set cmd '$$begin raise notice ''%'', ' :'var' ';
    end;$$;'

    postgres=# do :cmd;

    NOTICE:  Hello, World!

    DO

    
    -----
Pavel Luzanov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
    On 05.03.2018 17:02, Pavel Luzanov
      wrote:

    
      On 05.03.2018 16:56, Pavel Stehule wrote:

       
                               I
                                can't use psql variable in the DO
                                command. Is it intentional behavior?

                              
                              yes. psql variables living on client
                                side, and are not accessible from server
                                side . DO command is executed on server
                                side.

                              
                   But SELECT command also executed on a server
                  side ))

                  I thought that the command is sent to the server after
                  variable's replacement.

                  
              The psql variables are injected into SQL string
                before execution (before SQL string is sent to server).
                But this injection is disabled inside strings - and body
                of DO command is passed as string.

              
      Yes, now I
          understand this. But at first glance
          this is not an obvious behavior.

      
      -----
Pavel Luzanov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company