TP5.1 数据库查询汇总

第一类查询：简单查询，无链接

$where['字段名']='查询值'(等于)；
$where['字段名']=['in',查询数组];
$where['字段名']=['like','%匹配字符串%'];
$where['字段名']=['is','NULL'];
$where['字段名']=['between','1,3'];

$need=Db::name('表名')/model("表名");
    ->field('字段名1,字段名2,distinct 去重查询字段名,COUN(计算总数：1：字段名)')
    ->where($where)
    ->select()/查询单条：->find();

第二类查询：连表查询

$where['字段名']='查询值'(等于)；
$where['字段名']=['in',查询数组];
$where['字段名']=['like','%匹配字符串%'];
$where['字段名']=['is','NULL'];

$need=Db::name('表名:如dbnameone')/model("表名");
    ->alias('主表别名：dbone')
    ->join('连表名:dbnametwo 连表别名:dbtwo','连接条件，如：dbone.id=dbtwo.dbone_id','LEFT/RIGHT:可不填，默认INNER JOIN')
    ->field('字段名1,字段名2,distinct 去重查询字段名,COUN(计算总数：1：字段名)')->where($where)->select();(查询单条：->find())

第三类查询：原生sql查询

$sort = db()->query("SELECT COUNT(1) AS cnt FROM bigexp_meeting AS meet JOIN bigexp_guest AS guest ON guest.id = meet.guest_id WHERE meet.is_able=1 AND meet.meeting_id='".$val['detail_id']."' AND (guest.field_type = '' or guest.field_type = '其它' or guest.field_type is NULL) LIMIT 1");

注：以上除了第三类查询之外，所有表名均是去除前缀之后的表名