How to extract specified field data from mysql data table in php

Question

 $result = mysql_query("select * from brand order by yesterday_str");
                while($row = mysql_fetch_array($result))
                  {
                  echo "'".$row['yesterday_str']."'";
                  echo ",";
                  }

Now I can extract all field data in the brand table through the above method

There are 7 fields in the brand table: a, b, c, d, e, f, g.
How can I modify it to extract only the data of the 5 fields abcfg?

Answer 1

 $result = mysql_query("select a,b,c,f,g from brand order by yesterday_str");
                while($row = mysql_fetch_array($result))
                  {
                  echo "'".$row['yesterday_str']."'";
                  echo ",";
                  }
                  
                  //这样就好了吧？？？？