数据库有如下表
tb_file
tb_note
tb_note_answer
tb_word 下面这条语句什么意思 呢? answ.* 代表什么?$sql = "select tb_note.*,answ.* from tb_note left join";
$sql .= " (select noan_note_id,noan_content,noan_time from tb_note_answer) as answ ";
$sql .= " on answ.noan_note_id = tb_note.note_id ";
$sql .= " order by note_time desc ";
tb_file
tb_note
tb_note_answer
tb_word 下面这条语句什么意思 呢? answ.* 代表什么?$sql = "select tb_note.*,answ.* from tb_note left join";
$sql .= " (select noan_note_id,noan_content,noan_time from tb_note_answer) as answ ";
$sql .= " on answ.noan_note_id = tb_note.note_id ";
$sql .= " order by note_time desc ";
给查询设了别名 answ
这里是noan_note_id,noan_content,noan_time
中的所有字段,也就是tb_note_answer表中的noan_note_id,noan_content,noan_time 几个字段