SQL select AS-前置文本

Question

Is it possible to prepend text to an SQL select statement. eg:

var query = "SELECT id, " +
                   "picture " 
            "FROM people";

to

var query = "SELECT id, " +
                   "picture AS './directory/' + picture "
            "FROM people";

Answer 1

Yes. Something like this:

  var query = "SELECT id, " +
              "concat('./directory/',picture) AS  picture "
              "FROM people";

Bit more details: http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_concat

Answer 2

You are constructing the query as a string, so yes, you can do this. However, you have to insert the value as a constant. Something like:

var query = "SELECT id, " +
                   "picture AS " + directory " + "picture "
            "FROM people";

However, directory would need to be a value in the application and not the database (although another statement could read it).