而不仅仅是联接列所匹配的行,中检查指定表的

#mysql中 对于查询结果只突显n条一而再行的主题素材#

在领扣上碰见的二个主题素材:求满足条件的连接3行结果的来得

X city built a new stadium, each day many people visit it and the stats are saved as these columns: id, date, people;
Please write a query to display the records which have 3 or more consecutive rows and the amount of people more than 100(inclusive).
For example, the table stadium:
+------+------------+-----------+
| id   | date       | people    |
+------+------------+-----------+
| 1    | 2017-01-01 | 10        |
| 2    | 2017-01-02 | 109       |
| 3    | 2017-01-03 | 150       |
| 4    | 2017-01-04 | 99        |
| 5    | 2017-01-05 | 145       |
| 6    | 2017-01-06 | 1455      |
| 7    | 2017-01-07 | 199       |
| 8    | 2017-01-08 | 188       |
+------+------------+-----------+

For the sample data above, the output is:
+------+------------+-----------+
| id   | date       | people    |
+------+------------+-----------+
| 5    | 2017-01-05 | 145       |
| 6    | 2017-01-06 | 1455      |
| 7    | 2017-01-07 | 199       |
| 8    | 2017-01-08 | 188       |
+------+------------+-----------+

1.首先先进行结果集的询问

select id,date,people from stadium where people>=100;

2.给查询的结果集扩展三个自增列

SELECT @newid:=@newid+1 AS newid,test.* 
FROM(SELECT @newid:=0)r, test WHERE people>100

3.自增列和id的差值 一样即连续

SELECT @newid:=@newid+1 AS newid,test.* ,@cha:=id-@newid AS cha 
FROM(SELECT @newid:=0)r, test WHERE people>100

4.将一样的差值 放在同等张表中,并收取一连数量超出3的

select if(count(id)>=3,count_concat(id),null)e from(
SELECT @newid:=@newid+1 AS newid,test.* ,@cha:=id-@newid AS cha 
FROM(SELECT @newid:=0)r, test WHERE people>100)
as d group by cha

5.将上步获得的表和主表 获得所急需的

SELECT id,DATE,people FROM test,
(SELECT IF (COUNT(id)>3,GROUP_CONCAT(id),NULL)e 
FROM (SELECT @newid:=@newid+1 AS newid,test.* ,@cha:=id-@newid AS cha 
FROM(SELECT @newid:=0)r, test WHERE people>100)AS d   GROUP BY cha ) AS f 
WHERE f.e IS NOT NULL AND FIND_IN_SET(id,f.e);

听讲还足以用存款和储蓄进程来成功,可是自身没尝试,稍后尝试

以上

 

测试一:

4 wang null null   
------------------------------  

主意二:使用DBCC CHECKIDENT语句: DBCC CHECKIDENT在 SQL Server 二〇一〇 宝马X32中反省内定表的当下标记值,如有须求,则转移标记值。还可以够选择 DBCC CHECKIDENT 为标记列手动设置新的此时此刻标记值。

INSERT INTO bookcategory(category_id,category,parent_id) VALUES(1,'Computer',0);//钦点插入的逐条
INSERT INTO bookcategory VALUES(1,'计算机',0);//依照暗许的插入
INSERT INTO bookcategory(category_id,category,parent_id) VALUES(1,'计算机',0),(2,'xxx',3)(3,'xxxxx',4);//同不平日候插入多条数据
INSERT INTO bookcategory SELECT * FROM test WHERE id>5//将查询结果插入表中
CREATE TABLE TEXT(
category_id INT PRIMARY KEY AUTO_INCREMENT,
parent_id INT NOT NULL
)AUTO_INCREMENT=5; //auto_increment让这一列自动安装编号,暗中认可初阶值为,最终为设置早先值为5
ALTER TABLE bookcategory MODIFY category_id INT AUTO_INCREMENT=X//为已有表增添自增列
ALTER TABLE bookcategory MODIFY category_id INT;//去掉自增列
//有外键关系的话增多自增,要先去掉外键关系。
ALTER TABLE bookinfo DROP FOREIGN KEY fk_bcid//去掉外键
ALTER TABLE bookinfo ADD CONSTRAINT fk_bcid FOREIGN KEY(bookcdategory_id) REFERENCES bookcategory(category_id);//增加外键
SELECT price FROM bookinfo WHERE book_id=201501;//查询book_id为二〇一五01书的价格
SELECT * FROM readerinfo//查看读者音讯表
SELECT xxx,xxx,xxx FROM readerinfo//查询钦点列
SELECT xxx,xxx,xxx FROM readerinfo WHERE press='机械工业'//设置外加条件的询问
SELECT DISTINCT press FROM bookinfo;//突显不重复的查询
SELECT * FROM readerinfo WHERE age IS NULL;//查询为空的列
UPDATE readerinfo SET balance =balance -18.9*0.05 WHERE card_id='xxxxxxxx'//更新readerinfo那个表中的card_id为xxx的balance
DELETE FROM readerinfo WHERE card_id='201631513133'//单表数据记录的去除,不加where则为全数刨除
TRUNCATE TABLE readerinfo;//删除原表再次创下造空表
SELECT COUNT(*) FROM readerinfo WHERE sex='男'//对查询结果的分组
SELECT sex FROM readerinfo GROUP BY sex;//查询有些许种性别
SELECT sex COUNT(*) FROM readerinfo GROUP BY sex;//计算每一个性别的人头
SELECT sex FROM readerinfo GROUP BY sex WHERE COUNT(sex)>3;//也得以加限制条件。总括种种性其余人头
SELECT * FROM bookinfo O汉兰达DE纳瓦拉 BY price//对查询结果排序,默以为升序
SELECT * FROM bookinfo O福睿斯DE中华V BY price,store;//price同样的,遵照仓库储存排序
SELECT * FROM bookinfo ORDER BY price ASC,store DESC;//asc升序,desc降序
SELECT * FROM bookinfo LIMIT 3;//limit限制查询数量,偏移量为0从头,展现前三行
SELECT * FROM bookinfo LIMIT 2,2;//展现第二条语句的后五个语句
SELECT store,COUNT(*) FROM bookinfo GROUP BY store ORAV4DE瑞鹰 BY store DESC LIMIT 4;//计算仓库储存个数,并降序排序,并查阅前四条语句

 

 # --->22条记录

语法:

INSERT INTO bookcategory(category_id,category,parent_id) VALUES(1,'计算机',0);//指定插入的顺序


INSERT INTO bookcategory VALUES(1,'计算机',0);//按照默认的插入


INSERT INTO bookcategory(category_id,category,parent_id) VALUES(1,'计算机',0),(2,'xxx',3)(3,'xxxxx',4);//同时插入多条数据


INSERT INTO bookcategory SELECT * FROM test WHERE id>5//将查询结果插入表中


CREATE TABLE TEXT(

    category_id INT PRIMARY KEY AUTO_INCREMENT,

    parent_id INT NOT NULL

)AUTO_INCREMENT=5;    //auto_increment让这一列自动设置编号,默认初始值为,最后为设置初始值为5



ALTER TABLE bookcategory MODIFY category_id INT AUTO_INCREMENT=X//为已有表添加自增列



ALTER TABLE bookcategory MODIFY category_id INT;//去掉自增列


//有外键关系的话添加自增,要先去掉外键关系。


ALTER TABLE bookinfo DROP FOREIGN KEY fk_bcid//去掉外键


ALTER TABLE bookinfo ADD CONSTRAINT fk_bcid FOREIGN KEY(bookcdategory_id) REFERENCES bookcategory(category_id);//添加外键


SELECT price FROM bookinfo WHERE book_id=201501;//查询book_id为201501书的价格


SELECT * FROM readerinfo//查看读者信息表


SELECT xxx,xxx,xxx FROM readerinfo//查询指定列


SELECT xxx,xxx,xxx FROM readerinfo WHERE press='机械工业'//设置外加条件的查询


SELECT DISTINCT press FROM bookinfo;//显示不重复的查询


SELECT * FROM readerinfo WHERE age IS NULL;//查询为空的列


UPDATE readerinfo SET balance =balance -18.9*0.05 WHERE card_id='xxxxxxxx'//更新readerinfo这个表中的card_id为xxx的balance


DELETE FROM readerinfo WHERE card_id='201531513133'//单表数据记录的删除,不加where则为全部删除


TRUNCATE TABLE readerinfo;//删除原表再创建空表


SELECT COUNT(*) FROM readerinfo WHERE sex='男'//对查询结果的分组


SELECT sex FROM readerinfo GROUP BY sex;//查询有多少种性别


SELECT sex COUNT(*) FROM readerinfo GROUP BY sex;//统计每种性别的人数


SELECT sex FROM readerinfo GROUP BY sex WHERE COUNT(sex)>3;//也可以加限制条件。统计每种性别的人数


SELECT     * FROM bookinfo ORDER BY price//对查询结果排序,默认为升序


SELECT     * FROM bookinfo ORDER BY price,store;//price相同的,按照库存排序


SELECT * FROM bookinfo ORDER BY price ASC,store DESC;//asc升序,desc降序


SELECT * FROM bookinfo LIMIT 3;//limit限制查询数量,偏移量为0开始,显示前三行


SELECT * FROM bookinfo LIMIT 2,2;//显示第二条语句的后两个语句


SELECT store,COUNT(*) FROM bookinfo GROUP BY store ORDER BY store DESC LIMIT 4;//统计库存个数,并降序排序,并查看前四条语句

 

如表
-------------------------------------------------   
table1    
-------------------------------------------------   
id name  
1 lee
2 zhang

亲自去做:我们要重新设置表t1的当前标志值为0,sql如下:

 

 

##########那一个是SQL语句模型 BEGIN##########

参数: table_name:是要对其前段时间标记值实行检讨的表名。钦定的表必需包含标志列。表名必得符合标记符法则。 NORESEED:钦定不应改换当前标志值。 RESEED:钦命相应改成当前标志值。 new_reseed_value:用作标记列的当前值的新值。 WITH NO_INFOMSGS:撤除彰显全部音信性音信。

 

1
2
select t1.Userid from bbscs_role_user t1 left join bbscs_sales_income_stat t2 on t1.userid = t2.refid 
and t1.roleid = 'sales' and t2.type = 4 and t2.month '2012-02' and t2.amount != 0 and t2.id is null
1
select from table1 t1 left join table2 t2 on t1.id = t2.id

DBCC CHECKIDENT (   table_name   [, { NORESEED | { RESEED [,new_reseed_value ] } } ]  )  [ WITH NO_INFOMSGS ]

##跟顾客单位中间表关联,按机关id排序呈现。

1
2
3
4
5
6
7
8
9
create   table   table1(id   int,name   varchar(10));   
create   table   table2(id   int,score   int);   
insert   into   table1   select   '1','lee';
insert   into   table1   select   '2','zhang';
insert   into   table1   select   '3','steve';
insert   into   table1   select   '4','wang';   
insert   into   table2   select   '1','90';   
insert   into   table2   select   '2','100';   
insert   into   table2   select   '3','70';

dbcc checkident('t1',noreseed)

1
select userid from bbscs_role_user where roleid = 'sales'

-------------------------------------------------  

过多时候大家须求重新设置有些表的自增列,让自增列重新从1开首记数。最蠢的不二秘籍自然是把该表删掉再重新建表了。其实,还会有其余的方法可以重新载入参数自增列的值:

1
select from b t2 left join a t1 on t1.a1 = t2.b1 WHERE t1.a1 is null

 

正文来源:

##过滤出0销售职员(即未有贩卖记录的职工新闻列表)。

-------------结果-------------   
id name id score   
------------------------------   
1 lee 1 90   
2 zhang 2 100  

我们要询问表t1的日前标记值,sql如下:

 

3 70

dbcc checkident('t1',reseed,0)

table2

 

形式一:使用TRUNCATE TABLE语句: TRUNCATE TABLE删除表中的具备行,而不记录单个行删除操作,同期重新载入参数自增列。TRUNCATE TABLE 在效力上与未有WHERE子句的DELETE语句同样;不过,TRUNCATE TABLE 速度更加快,使用的系统财富和事业日志能源越来越少。

1
select refid from bbscs_sales_income_stat where type = 4 and month '2012-02' and amount != 0
1
2
select t1.Userid from bbscs_role_user t1 left join bbscs_sales_income_stat t2 on t1.userid = t2.refid 
and t1.roleid = 'sales' and t2.type = 4 and t2.month '2012-02' and t2.amount != 0 where t2.id is null;

 

3 70

#出售人士(客商脚色中间表)

##将SQL再次来到结果作为有的时候表来查询

1
select from table1 t1 left join table2 t2 on t1.id = t2.id WHERE t2.id is null

本文由必威发布于必威-数据,转载请注明出处:而不仅仅是联接列所匹配的行,中检查指定表的

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