CREATE DATABASE ADDRESSLIST; USE ADDRESSLIST; DROP TABLE IF EXISTS FRIEND; CREATE TABLE FRIEND (FRIEND_ID INTEGER NOT NULL AUTO_INCREMENT PRIMARY KEY , FRIEND_NAME VARCHAR(20) NOT N ......
String sqlCount="select count(*) from usertable where username='"+ userName+"'";这句话 什么意思啊! 这句话输出出来就是 select count(*) from usertable where username='你的变量 ......