SQL語言是一種在數據庫中進行交互的標準語言。SQL語句的使用涵蓋了從創建數據庫到刪除表和數據記錄等操作。對于開發者而言，學會了SQL語句，就掌握了管理并查詢數據的基礎知識。以下是SQL語句常用50條的內容。 一、基礎操作 1.創建數據庫: CREATE DATABASE database_name; 2.刪除數據庫: DROP DATABASE database_name; 3.創建表: CREATE TABLE table_name (column1 datatype, column2 datatype, column3 datatype, …); 4.刪除表: DROP TABLE table_name; 5.插入數據: INSERT INTO table_name (column1, column2, column3, …) VALUES (value1, value2, value3, …); 6.更新數據: UPDATE table_name SET column1 = value1, column2 = value2 WHERE some_column = some_value; 7.查詢數據: SELECT column1, column2, … FROM table_name; 8.刪除數據: 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.刪除列: ALTER TABLE table_name DROP COLUMN column_name; 13.計數: SELECT COUNT(column_name) FROM table_name; 14.合計: 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.分組: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name; 19.篩選: SELECT column1, column2, … FROM table_name WHERE some_column = some_value; 20.排除重復行: SELECT DISTINCT column1, column2, … FROM table_name; 二、向表中添加新記錄 21. 插入一行 (不指定行數): INSERT INTO table_name VALUES (value1, value2, value3, …); 22. 插入多行記錄: INSERT INTO table_name (column1, column2, column3, …) VALUES (value1, value2, value3, …), (value4, value5, value6, …); 23. 插入選擇: INSERT INTO table2 COLUMN (column1, column2, column3, …) SELECT (column1, column2, column3, …) FROM table1; 三、更新現有記錄 24. 更新單個字段: UPDATE table_name SET column_name = new_value WHERE some_column = some_value; 25. 更新多個字段: UPDATE table_name SET column1 = new_value1, column2 = new_value2 WHERE some_column = some_value; 26. 更新按條件: 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. 更新數據類型: ALTER TABLE table_name ALTER COLUMN column_name new_datatype; 四、查詢記錄 31. 簡單查詢: SELECT column1, column2 FROM table_name; 32. 查詢所有數據: SELECT * FROM table_name; 33. 條件查詢: SELECT column1, column2 FROM table_name WHERE column_name = some_value; 34. 值域查詢: SELECT column1, column2 FROM table_name WHERE column_name BETWEEN some_value_1 AND some_value_2; 35. IN查詢: SELECT column1, column2 FROM table_name WHERE column_name IN (value1, value2, …); 36. NOT IN查詢: SELECT column1, column2 FROM table_name WHERE column_name NOT IN (value1, value2, …); 37. NOT查詢: SELECT column1, column2 FROM table_name WHERE column_name != some_value; 38. 組合查詢: SELECT column1, column2 FROM table_name WHERE column_name = some_value_1 OR column_name = some_value_2; 39. AND查詢: SELECT column1, column2 FROM table_name WHERE column_name = some_value_1 AND column_name = some_value_2; 40. 模糊查詢: 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. 制定排序條件: SELECT column1, column2 FROM table_name ORDER BY column_name_1 ASC, column_name_2 DESC; 43. 分組查詢: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name; 44. 分組條件查詢: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name HAVING COUNT(*) > some_value; 45. JOIN查詢: SELECT table1.column1, table 2.column2 FROM table1 JOIN table2 ON table1.unique_column = table2.unique_column; 46. LEFT JOIN查詢: SELECT table1.column1, table 2.column2 FROM table1 LEFT JOIN table2 ON table1.unique_column = table2.unique_column; 47. RIGHT JOIN查詢: SELECT table2.column2, table1.column1 FROM table1 RIGHT JOIN table2 ON table1.unique_column = table2.unique_column; 48. FULL JOIN查詢: SELECT table1.column1, table2.column2 FROM table1 FULL JOIN table2 ON table1.unique_column = table2.unique_column; 49. 自然連接: SELECT table1.column1, table2.column2 FROM table1 NATURAL JOIN table2; 50. 下一頁查詢: SELECT column1, column2 FROM table_name LIMIT start_index, page_size; 總結 以上為SQL語句常用50條的內容，涉及SQL語言的基礎操作、向表中添加新記錄、更新現有記錄和查詢記錄等操作。掌握這些SQL語句對開發者來說非常重要，在編寫數據庫應用時能夠高效地管理數據。
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