limit 在語句最後，起到限制條目的作用。它的語法

limit [offset,]N
offset 偏移量,如果offset不寫，預設是0，N
N  取出的條目

1、取出觸發器id最高的前三個專案

mysql> select functionid,itemid,triggerid,function from functions order by triggerid desc limit 3;

2、取出觸發器id 4,5,6 高的欄目

mysql> select functionid,itemid,triggerid,function from functions order
 
 by triggerid desc limit 3,3;

3、取出每個功能裡面fuctionid最大的欄目
思路：建立臨時表，如果不夠建表，需要用到子查詢，子查詢的結果可以看成一張表

#構建臨時表
mysql> select functionid,itemid,triggerid,function from functions order by function,functionid desc;

#用子查詢
select * from (select functionid,itemid,triggerid,function from functions order
 
 by function,functionid desc) as tmp group by function;

mysql的5中查詢子句

mysql的5中查詢子句之一where條件查詢
http://blog.csdn.net/m0_37886429/article/details/73224579

mysql的5中查詢子句之二group by分組查詢
http://blog.csdn.net/m0_37886429/article/details/73276996

mysql的5中查詢子句之三having條件查詢
http://blog.csdn.net/m0_37886429/article/details/73323970
 


mysql的5中查詢子句之四order by排序查詢
http://blog.csdn.net/m0_37886429/article/details/73457866

mysql的5中查詢子句之五limit限制查詢
http://blog.csdn.net/m0_37886429/article/details/73481387