Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
207 views
in Technique[技术] by (71.8m points)

php - How to SELECT DEFAULT value of a field

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;
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)
"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 ;"

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...