SQL语言是一种在数据库中进行交互的标准语言。SQL语句的使用涵盖了从创建数据库到删除表和数据记录等操作。对于开发者而言，学会了SQL语句，就掌握了管理并查询数据的基础知识。以下是SQL语句常用50条的内容。 一、基础操作 1.创建数据库: CREATE DATABASE database_name; 2.删除数据库: DROP DATABASE database_name; 3.创建表: CREATE TABLE table_name (column1 datatype, column2 datatype, column3 datatype, …); 4.删除表: DROP TABLE table_name; 5.插入数据: INSERT INTO table_name (column1, column2, column3, …) VALUES (value1, value2, value3, …); 6.更新数据: UPDATE table_name SET column1 = value1, column2 = value2 WHERE some_column = some_value; 7.查询数据: SELECT column1, column2, … FROM table_name; 8.删除数据: DELETE FROM table_name WHERE some_column = some_value; 9.排序: SELECT column1, column2, … FROM table_name ORDER BY column1 ASC/DESC; 10.重命名表: RENAME TABLE table_name TO new_table_name; 11.添加列: ALTER TABLE table_name ADD column_name datatype; 12.删除列: ALTER TABLE table_name DROP COLUMN column_name; 13.计数: SELECT COUNT(column_name) FROM table_name; 14.合计: SELECT SUM(column_name) FROM table_name; 15.平均值: SELECT AVG(column_name) FROM table_name; 16.最大值: SELECT MAX(column_name) FROM table_name; 17.最小值: SELECT MIN(column_name) FROM table_name; 18.分组: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name; 19.筛选: SELECT column1, column2, … FROM table_name WHERE some_column = some_value; 20.排除重复行: SELECT DISTINCT column1, column2, … FROM table_name; 二、向表中添加新记录 21. 插入一行 (不指定行数): INSERT INTO table_name VALUES (value1, value2, value3, …); 22. 插入多行记录: INSERT INTO table_name (column1, column2, column3, …) VALUES (value1, value2, value3, …), (value4, value5, value6, …); 23. 插入选择: INSERT INTO table2 COLUMN (column1, column2, column3, …) SELECT (column1, column2, column3, …) FROM table1; 三、更新现有记录 24. 更新单个字段: UPDATE table_name SET column_name = new_value WHERE some_column = some_value; 25. 更新多个字段: UPDATE table_name SET column1 = new_value1, column2 = new_value2 WHERE some_column = some_value; 26. 更新按条件: UPDATE table_name SET column_name = new_value WHERE some_column = some_value_2; 27. 更新空值: UPDATE table_name SET column_name = NULL WHERE some_column = some_value; 28. 更新非空值: UPDATE table_name SET column_name = NOT NULL WHERE some_column = some_value; 29. 更新自增列: UPDATE table_name SET column_name = column_name + 1 WHERE some_column = some_value; 30. 更新数据类型: ALTER TABLE table_name ALTER COLUMN column_name new_datatype; 四、查询记录 31. 简单查询: SELECT column1, column2 FROM table_name; 32. 查询所有数据: SELECT * FROM table_name; 33. 条件查询: SELECT column1, column2 FROM table_name WHERE column_name = some_value; 34. 值域查询: SELECT column1, column2 FROM table_name WHERE column_name BETWEEN some_value_1 AND some_value_2; 35. IN查询: SELECT column1, column2 FROM table_name WHERE column_name IN (value1, value2, …); 36. NOT IN查询: SELECT column1, column2 FROM table_name WHERE column_name NOT IN (value1, value2, …); 37. NOT查询: SELECT column1, column2 FROM table_name WHERE column_name != some_value; 38. 组合查询: SELECT column1, column2 FROM table_name WHERE column_name = some_value_1 OR column_name = some_value_2; 39. AND查询: SELECT column1, column2 FROM table_name WHERE column_name = some_value_1 AND column_name = some_value_2; 40. 模糊查询: SELECT column1, column2 FROM table_name WHERE column_name LIKE pattern; 41. 指定排序: SELECT column1, column2 FROM table_name ORDER BY column_name ASC; 42. 制定排序条件: SELECT column1, column2 FROM table_name ORDER BY column_name_1 ASC, column_name_2 DESC; 43. 分组查询: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name; 44. 分组条件查询: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name HAVING COUNT(*) > some_value; 45. JOIN查询: SELECT table1.column1, table 2.column2 FROM table1 JOIN table2 ON table1.unique_column = table2.unique_column; 46. LEFT JOIN查询: SELECT table1.column1, table 2.column2 FROM table1 LEFT JOIN table2 ON table1.unique_column = table2.unique_column; 47. RIGHT JOIN查询: SELECT table2.column2, table1.column1 FROM table1 RIGHT JOIN table2 ON table1.unique_column = table2.unique_column; 48. FULL JOIN查询: SELECT table1.column1, table2.column2 FROM table1 FULL JOIN table2 ON table1.unique_column = table2.unique_column; 49. 自然连接: SELECT table1.column1, table2.column2 FROM table1 NATURAL JOIN table2; 50. 下一页查询: SELECT column1, column2 FROM table_name LIMIT start_index, page_size; 总结 以上为SQL语句常用50条的内容，涉及SQL语言的基础操作、向表中添加新记录、更新现有记录和查询记录等操作。掌握这些SQL语句对开发者来说非常重要，在编写数据库应用时能够高效地管理数据。
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