From d7921619d83c1e2f133c79993b00c3540606cac1 Mon Sep 17 00:00:00 2001
From: unknown <“921978039@qq.com”>
Date: Wed, 7 Sep 2022 21:00:23 +0800
Subject: [PATCH] 0

---
 .../9.7\344\275\234\344\270\232.md"           |  84 ++++++++++++++
 .../\347\254\224\350\256\260/9.7.md"          | 107 ++++++++++++++++++
 2 files changed, 191 insertions(+)
 create mode 100644 "05  \351\273\204\347\202\234\346\235\260/\344\275\234\344\270\232/9.7\344\275\234\344\270\232.md"
 create mode 100644 "05  \351\273\204\347\202\234\346\235\260/\347\254\224\350\256\260/9.7.md"

diff --git "a/05  \351\273\204\347\202\234\346\235\260/\344\275\234\344\270\232/9.7\344\275\234\344\270\232.md" "b/05  \351\273\204\347\202\234\346\235\260/\344\275\234\344\270\232/9.7\344\275\234\344\270\232.md"
new file mode 100644
index 0000000..f6dd8ee
--- /dev/null
+++ "b/05  \351\273\204\347\202\234\346\235\260/\344\275\234\344\270\232/9.7\344\275\234\344\270\232.md"	
@@ -0,0 +1,84 @@
+```
+use banktest;
+go
+select * from AccountInfo  --个人信息
+select * from BankCard  --银行卡信息
+select * from CardStateChange  --银行卡状态更改表
+select * from CardTransfer  --转账表
+select * from CardExchange  --交易记录
+```
+
+--1.	关羽的银行卡号为"6225547858741263"，查询出余额比关羽多的银行卡信息，显示卡号，身份证，姓名，余额。
+
+```
+declare @qqq int
+select @qqq=CardMoney from BankCard where CardNo = '6225547858741263'
+select b.CardNo 卡号,b.CardMoney 余额,a.RealName 姓名,a.AccountCode 身份证 from BankCard as b
+join AccountInfo a on a.AccountId=b.AccountId
+where b.CardMoney>@qqq
+```
+
+--2.	从所有账户信息中查询出余额最高的交易明细(存钱取钱信息)。
+
+```
+--select max(MoneyInBank)存钱,Max(MoneyOutBank)取款 from CardExchange
+declare @inmoney money
+declare @outmoney money
+select @inmoney=max(MoneyInBank),@outmoney=max(MoneyOutBank) from CardExchange
+if @inmoney>0
+  begin
+     print '存入'+cast(@inmoney as char)+'元'
+  end
+  if @outmoney>0
+	  begin
+	    print '取出'+@outmoney+'元'
+	  end
+else
+   print '没有交易记录'
+```
+
+--3.	查询有取款记录的银行卡及账户信息，显示卡号，身份证，姓名，余额。
+
+```
+select C1.CardNo,B1.CardMoney,A1.AccountCode,A1.RealName from CardExchange as C1 join BankCard as B1 on C1.CardNo=B1.CardNo
+join AccountInfo as A1 on B1.AccountId=A1.AccountId
+where MoneyOutBank !=0
+```
+
+--4.	查询出没有存款记录的银行卡及账户信息，显示卡号，身份证，姓名，余额。
+
+```
+select b.CardNo'卡号',a.AccountCode'身份证',a.RealName'姓名',b.CardMoney'余额' from AccountInfo as a join BankCard as b on a.AccountId=b.AccountId
+where a.AccountId in (select AccountId from BankCard where CardMoney =0.00)
+```
+
+--5.	关羽的银行卡号为"6225547858741263",查询当天是否有收到转账。
+
+```
+declare @Transfermoney money
+select @Transfermoney=TransferMoney from CardTransfer where CardNoIn=6225547858741263
+if @Transfermoney>0
+ begin
+   print'收到转账'
+ end
+else
+   print'没收到转账'
+```
+
+--6.	查询出交易次数（存款取款操作）最多的银行卡账户信息，显示：卡号，身份证，姓名，余额，交易数。
+
+```
+select s2.CardMoney,s2.CardNo,s1.CardNo,count(s1.CardNo)'交易数' from CardExchange as s1
+left join BankCard as s2 on s1.CardNo = s2.CardNo
+group by s1.CardNo
+```
+
+--7.	查询出没有转账交易记录的银行卡账户信息，显示卡号，身份证，姓名，余额。
+
+```
+select s2.CardNo'卡号',s3.AccountCode'身份证',s3.RealName'姓名',s2.CardMoney'余额' from CardTransfer as s1
+right join BankCard as s2 on s1.CardNoOut=s2.CardNo
+right join AccountInfo as s3 on s2.AccountId = s3.AccountId
+where s1.CardNoOut is null
+```
+
diff --git "a/05  \351\273\204\347\202\234\346\235\260/\347\254\224\350\256\260/9.7.md" "b/05  \351\273\204\347\202\234\346\235\260/\347\254\224\350\256\260/9.7.md"
new file mode 100644
index 0000000..86d9e9c
--- /dev/null
+++ "b/05  \351\273\204\347\202\234\346\235\260/\347\254\224\350\256\260/9.7.md"	
@@ -0,0 +1,107 @@
+# 连接
+
+### 例子：
+
+```
+select sName,sAge,
+   case
+      when english <60 then '不及格'
+      when english IS null then '缺考' 
+      else CONVERT(nvarchar, english)
+   end as'英语成绩'
+from student as s
+left join Score as c on s.sid =c.sid
+
+内连接  inner join...on...
+        查询满足on后面条件的数据
+           
+
+--练习：将StuScore成绩表中的学生成绩用五分制显示。
+--				5分：80分以上
+--				4分：60～79分
+--				3分：40～59分
+--				2分：20～39分
+--				1分：0～19分
+select stuName,stuID,english,
+case 
+ when english>=80 then '5分'
+ when english>=60 then '4分'
+ when english>=40 then '3分'
+ when english>=20 then '2分'
+ when english>=0 then '1分'
+ else '0分'
+end '5分制'
+from StuScore
+inner join StuInfo on StuScore.StuID = StuInfo.StuNo
+```
+
+## 批处理语句
+
+go语句特点:
+
+1. 等待go语句前的代码执行完成后，再执行go后面的代码。
+2. 批处理语句的结束标志。
+
+```
+--下面的@num变量作用域为全局
+--declare @num int
+--set @num = 0
+
+--下面的@num变量的作用域是局部，只在两个go之间可以使用，最后一行代码会报错
+--.........sql代码
+--go
+--declare @num int
+--set @num = 0
+--go
+--set @num = 1
+```
+
+### 比较运算符
+
+SQLServer中有三个关键字可以修改比较[运算符](https://gitee.com/link?target=https%3A%2F%2Fso.csdn.net%2Fso%2Fsearch%3Fq%3D%E8%BF%90%E7%AE%97%E7%AC%A6%26spm%3D1001.2101.3001.7020)：All、Any和Some，其中Some和Any等价
+
+```
+set nocount on
+  
+use tempdb
+go
+  
+if (object_id ('t1') is not null)drop table t1
+create table t1 (n int)
+insert into t1 select 2 unionselect 3  
+  
+if (object_id ('t2') is not null)drop table t2
+create table t2 (n int)
+insert into t2 select 1 unionselect 2 union select 3 union select 4
+  
+-- t1表数据 2,3
+-- t2表数据 1,2,3,4
+-- '>all' 表示:t2表中列n的数据大于t1表中列n的数据的数，结果只有4.
+select * from t2 where n > all(select n from t1 )    --4
+select * from t2 where n > any(select n from t1 )    --3,4
+select * from t2 where n > some(selectn from t1)      --3,4
+  
+select * from t2 where n = all(select n from t1 )    --无数据
+select * from t2 where n = any(select n from t1 )    --2,3
+select * from t2 where n = some(selectn from t1)      --2,3
+  
+select * from t2 where n < all(select n from t1 )    --1
+select * from t2 where n < any(select n from t1 )    --1,2
+select * from t2 where n < some(selectn from t1)      --1,2
+  
+select * from t2 where n <>all (select n from t1 )    --1,4
+select * from t2 where n <>any (select n from t1 )    --1,2,3,4
+select * from t2 where n <>some(select n from t1)      --1,2,3,4
+set nocount off
+```
+
+注意：
+
+1. =any 与in 等效.
+2. 如果t1中包含null数据，那么所有All相关的比较运算将不会返回任何结果。因为t1和t2表的null的存在他们和notexists之类的比较符会有一些区别。 比如下面两句
+
+```
+select * from t2 a where not exists(select1 from t1 where n>=a.n) 
+ 
+select * from t2 where  n > all(select n from t1) 
+```
\ No newline at end of file
-- 
Gitee