SQL(Structured Query Language)是用于管理关系数据库的标准编程语言,以下是一些基本的SQL语句示例,涵盖了创建、查询、更新和删除数据库中的数据的常见操作:
1. **创建表**:
CREATE TABLE table_name ( column1 datatype, column2 datatype, column3 datatype, ... );
2. **插入数据**:
INSERT INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...);
3. **查询数据**:
SELECT column1, column2, ... FROM table_name WHERE condition;
4. **更新数据**:
UPDATE table_name SET column1 = value1, column2 = value2, ... WHERE condition;
5. **删除数据**:
DELETE FROM table_name WHERE condition;
6. **创建索引**:
CREATE INDEX index_name ON table_name (column1, column2, ...);
7. **删除索引**:
DROP INDEX index_name;
8. **创建视图**:
CREATE VIEW view_name AS SELECT column1, column2, ... FROM table_name WHERE condition;
9. **删除视图**:
DROP VIEW view_name;
10. **添加主键**:
ALTER TABLE table_name ADD PRIMARY KEY (column1, column2, ...);
11. **删除主键**:
ALTER TABLE table_name DROP PRIMARY KEY;
12. **连接表**:
SELECT column1, column2, ... FROM table1 INNER JOIN table2 ON table1.column_name = table2.column_name;
这只是SQL语句的冰山一角,SQL语言非常丰富,包括聚合函数、子查询、事务处理、存储过程、触发器等高级功能,为了全面掌握SQL,建议参考专业的数据库教材或在线教程,并多进行实践练习。