sql语句大全实例教程
时间: 2023-08-31 07:12:54 浏览: 45
以下是一些常用的 SQL 语句实例:
1. 创建表:
```sql
CREATE TABLE employee (
emp_id INT PRIMARY KEY,
emp_name VARCHAR(50),
emp_salary DECIMAL(10,2)
);
```
2. 插入数据:
```sql
INSERT INTO employee (emp_id, emp_name, emp_salary)
VALUES (1, 'John Doe', 50000.00);
```
3. 更新数据:
```sql
UPDATE employee SET emp_salary = 55000.00 WHERE emp_id = 1;
```
4. 删除数据:
```sql
DELETE FROM employee WHERE emp_id = 1;
```
5. 查询数据:
```sql
SELECT * FROM employee WHERE emp_salary > 50000.00;
```
6. 连接表:
```sql
SELECT employee.emp_name, department.dept_name
FROM employee
INNER JOIN department ON employee.emp_id = department.emp_id;
```
7. 分组:
```sql
SELECT department.dept_name, COUNT(employee.emp_id)
FROM employee
INNER JOIN department ON employee.emp_id = department.emp_id
GROUP BY department.dept_name;
```
8. 排序:
```sql
SELECT emp_name, emp_salary
FROM employee
ORDER BY emp_salary DESC;
```
9. 使用函数:
```sql
SELECT emp_name, UPPER(emp_name)
FROM employee;
```
以上是 SQL 语句的一些常见用法,可以根据具体需求进行调整和扩展。