SQL嵌套查询语句的报错问题

Question

String sql = "select * from msgInfo where ID in(select top 15 ID from msgInfo where chatRoom=? Order by chatTime DESC) order by chatTime";
String userName=session.getAttribute("_USER").toString();
PreparedStatement ps = conn.preparedStatement(sql);
ps.setString(1,session.getAttribute("_CHAT_ROOM").toString());
ResultSet rs = conn.executeQuery();

这语句有问题吗，怎么老报错，没道理啊

ou have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '15 ID from msgInfo where chatRoom='dragon inn' Order by chatTime DESC) order by ' at line 1
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '15 ID from msgInfo where chatRoom='dragon inn' Order by chatTime DESC) order by ' at line 1

Answer 1

一,Mysql 应该是不支持top关键词的,你应该用limit
二.limit 关键词不能和 in 一起使用,所以你要在limit子查询外再嵌套一层子查询.