mysql快速复制数据,多条件查询技巧

mysql快速复制数据

INSERT INTO 目标表 (字段1, 字段2, ...) SELECT 字段1, 字段2, ... FROM 来源表;

数据库多条件查询技巧

public ResultSet gradeList(Connection con,PageBean pageBean,Grade grade)throws Exception{
//StringBuffer用于字符串的追加
StringBuffer sb=new StringBuffer("select * from t_grade");
//isNotEmpty是判断是否为空的方法
if(grade!=null && StringUtil.isNotEmpty(grade.getGradeName())){
//追加sql语句
sb.append(" and gradeName like '%"+grade.getGradeName()+"%'");
}
if(pageBean!=null){
sb.append(" limit "+pageBean.getStart()+","+pageBean.getRows());
}
//把StringBuffer类型转化为String,把sb(sql语句)的第一个and替换为where
PreparedStatement pstmt=con.prepareStatement(sb.toString().replaceFirst("and", "where"));
return pstmt.executeQuery();
}