SQL 查询 (Queries)
1. 基本查询 (SELECT)
SELECT column1, column2 FROM table_name;
SELECT * FROM table_name;
2. 条件筛选 (WHERE)
SELECT * FROM table_name WHERE condition;
- 运算符:
=,<>,>,<,>=,<=,BETWEEN,LIKE,IN.
3. 排序 (ORDER BY)
SELECT * FROM table_name ORDER BY column1 ASC, column2 DESC;
4. 插入、更新与删除 (DML)
- INSERT INTO:
INSERT INTO table_name (col1, col2) VALUES (val1, val2); - UPDATE:
UPDATE table_name SET col1 = val1 WHERE condition; - DELETE:
DELETE FROM table_name WHERE condition;