ACCESS 有一个自动编号的字段名为ID SQl为: String sql_del = "delete from guestbook where ID='"+del_id+"'"; del.executeQuery(sql_del); 不管我的del_id转为那一种类型数据系统都提示"数据类型不匹配" (long int String 等类型我都试过,还是不行啊!)
String sql_del = "delete from guestbook where ID="+del_id; 试试
或者是: String sql_del = "delete from guestbook where to_number(ID)=to_number('"+del_id+"')"; 试试
为什么使用 String sql_del = "delete from guestbook where ID="+del_id; 或者 String sql_del = "delete from guestbook where ID="+del_id+""; 这两种方法就能删除呢? 而: String sql_del = "delete from guestbook where to_number(ID)=to_number('"+del_id+"')";或者 String sql_del = "delete from guestbook where ID='"+del_id+"'";就删除不成功呢? 请各位好汉探讨一下!
String sql_del = "delete from guestbook where ID="+del_id;这句话实际执行的SQL语句为delete from guestbook where ID=1234 ID是作为数字型的,而另一句: String sql_del = "delete from guestbook where ID='"+del_id+"'"; 实际执行的SQL语句为: delete from guestbook where ID='1234';把ID作为字符型处理,当然会变成类型不匹配。
SQl为:
String sql_del = "delete from guestbook where ID='"+del_id+"'";
del.executeQuery(sql_del);
不管我的del_id转为那一种类型数据系统都提示"数据类型不匹配"
(long int String 等类型我都试过,还是不行啊!)
试试
String sql_del = "delete from guestbook
where to_number(ID)=to_number('"+del_id+"')";
试试
String sql_del = "delete from guestbook where ID="+del_id;
或者
String sql_del = "delete from guestbook where ID="+del_id+"";
这两种方法就能删除呢?
而:
String sql_del = "delete from guestbook where to_number(ID)=to_number('"+del_id+"')";或者
String sql_del = "delete from guestbook
where ID='"+del_id+"'";就删除不成功呢?
请各位好汉探讨一下!
我懷疑是變量del_id的值不是數字,而是null
String sql_del = "delete from guestbook where ID='"+del_id+"'";
实际执行的SQL语句为:
delete from guestbook where ID='1234';把ID作为字符型处理,当然会变成类型不匹配。