How to SELECT DEFAULT value of a field

2019-01-09 15:57发布

I can't seem to find or write a sqlquery that SELECTS the DEFAULT VALUE

(and I don't think I can generate it in phpmyadmin for me to copy)

I tried to SELECT it as if it was a record but to no avail...

 $defaultValue_find = mysql_query(
         "SELECT $group FROM grouptable WHERE $group='DEFAULT'")  
      or die("Query failed:".mysql_error());
 $defaultValue_fetch = mysql_fetch_row($defaultValue_find);
 $defaultValue = $defaultValue_fetch[0];
 echo $defaultValue;

1条回答
叼着烟拽天下
2楼-- · 2019-01-09 16:36
"SELECT $group FROM grouptable WHERE $group=DEFAULT( $group ) "

Or I think better:

"SELECT DEFAULT( $group ) FROM grouptable LIMIT 1 "

Update - correction

As @Jeff Caron pointed, the above will only work if there is at least 1 row in grouptable. If you want the result even if the grouptable has no rows, you can use this:

"SELECT DEFAULT( $group ) 
 FROM (SELECT 1) AS dummy
   LEFT JOIN grouptable 
     ON True
 LIMIT 1 ;"
查看更多
登录 后发表回答