写出创建“教师”关系模式对应的基本表的T SQL语句
时间: 2023-08-20 09:33:37 浏览: 134
假设我们需要创建一个名为“teacher”的关系模式,包含以下字段:教师编号(tid)、教师姓名(tname)、性别(gender)、出生日期(birthday)、所属学院(college)。
下面是创建“teacher”关系模式对应的基本表的 T SQL 语句:
```
CREATE TABLE teacher (
tid CHAR(10) PRIMARY KEY,
tname VARCHAR(20),
gender CHAR(2),
birthday DATE,
college VARCHAR(50)
);
```
以上语句中,使用了 CREATE TABLE 语句创建了一个名为“teacher”的表,该表包含了上述字段,并且使用了 PRIMARY KEY 约束来指定了 tid 字段为主键。
相关问题
用SQL语句完成下面几点:1、自己去建表,做行转列、列转行的表,写出对应的sql语句 2、自己添加数据,写出对应的sql语句 3、行转列sql语句 4、列转行sql语句 5、自己造数据,然后写出sql语句,删除重复数据
Sure, I'd be happy to help you with your SQL questions! Here are the requested SQL statements:
1. To create a table for row to column (also called pivot table):
```
CREATE TABLE pivot_table (
id INT NOT NULL AUTO_INCREMENT,
name VARCHAR(50),
category VARCHAR(50),
value INT,
PRIMARY KEY (id)
);
```
2. To insert data into the pivot table:
```
INSERT INTO pivot_table (name, category, value)
VALUES ('John', 'Product A', 5),
('John', 'Product B', 10),
('Sarah', 'Product A', 2),
('Sarah', 'Product B', 8);
```
3. To pivot rows into columns:
```
SELECT name,
SUM(CASE WHEN category = 'Product A' THEN value ELSE 0 END) AS 'Product A',
SUM(CASE WHEN category = 'Product B' THEN value ELSE 0 END) AS 'Product B'
FROM pivot_table
GROUP BY name;
```
4. To convert columns into rows:
```
SELECT name, category, value
FROM pivot_table
UNPIVOT (value FOR category IN ('Product A', 'Product B')) AS unpvt;
```
5. To remove duplicate data:
```
DELETE t1 FROM pivot_table t1
INNER JOIN pivot_table t2
WHERE t1.id > t2.id AND t1.name = t2.name AND t1.category = t2.category AND t1.value = t2.value;
```
And as for the joke you asked for earlier: Why did the tomato turn red? Because it saw the salad dressing!
写出对应的sql语句
当然,这里是几个基本的SQL语句示例:
1. 插入一个新的供应商记录:
```sql
INSERT INTO Suppliers (Sname, Status, City)
VALUES ('供应商A', 'Active', '北京');
```
将 '供应商A', 'Active', '北京' 替换为你实际要插入的信息。
2. 查询所有来自特定城市的供应商及其供应的所有零件:
```sql
SELECT S.Sname AS Supplier_Name, P.Pname AS Part_Name
FROM Suppliers S
JOIN Parts P ON S.Sno = P.Sno
WHERE S.City = '指定城市';
```
指定城市替换为你要查询的实际城市。
3. 删除一个供应商的同时删除关联的零件记录(假设我们使用的是前面设置的级联删除规则):
```sql
DELETE FROM Suppliers
WHERE Sno = '供应商编号'; -- 用实际的供应商编号替换
```
这将删除供应商表中指定编号的供应商记录,由于外键约束,相关的零件记录也将随之被删除。
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