达梦数据库sql语法及示例
时间: 2024-06-13 10:01:47 浏览: 533
达梦数据库(Damo DM)是基于Oracle SQL标准的数据库管理系统,其SQL语法与标准SQL非常相似,但也有一些特有的扩展和优化。以下是一些基本的SQL语法概念和示例:
1. **SQL查询**:
```sql
SELECT column1, column2
FROM table_name
WHERE condition;
```
示例:选择`employees`表中的`name`和`salary`列,当`salary`大于50000时:
```sql
SELECT name, salary
FROM employees
WHERE salary > 50000;
```
2. **数据插入**:
```sql
INSERT INTO table_name (column1, column2)
VALUES (value1, value2);
```
示例:向`employees`表中插入新员工数据:
```sql
INSERT INTO employees (name, salary)
VALUES ('John Doe', 60000);
```
3. **更新操作**:
```sql
UPDATE table_name
SET column = new_value
WHERE condition;
```
示例:将`salary`为60000的员工涨薪10%:
```sql
UPDATE employees
SET salary = salary * 1.10
WHERE salary = 60000;
```
4. **删除记录**:
```sql
DELETE FROM table_name
WHERE condition;
```
示例:删除`salary`小于30000的员工记录:
```sql
DELETE FROM employees
WHERE salary < 30000;
```
5. **创建表**:
```sql
CREATE TABLE table_name (
column1 datatype,
column2 datatype,
...
);
```
示例:创建`employees`表:
```sql
CREATE TABLE employees (
id INT PRIMARY KEY,
name VARCHAR(50),
salary DECIMAL(10, 2)
);
```
**相关问题**:
1. 达梦数据库支持哪些数据类型?
2. 如何在达梦数据库中创建视图?
3. 你能解释一下达梦数据库的事务管理吗?
阅读全文