MySQL是一種常用的關(guān)系型數(shù)據(jù)庫,常用的關(guān)鍵字有很多,此處僅列舉一些常用的關(guān)鍵字及其用法:
SELECT:用于查詢表中的數(shù)據(jù),其語法格式為: SELECT column1, column2, ... FROM table_name WHERE conditions; 例如: SELECT * FROM students WHERE age >18;FROM:用于指定要查詢的數(shù)據(jù)表,其語法格式為: SELECT column1, column2, ... FROM table_name WHERE conditions; 例如: SELECT name, age FROM students WHERE gender='female';WHERE:用于指定查詢的條件,其語法格式為: SELECT column1, column2, ... FROM table_name WHERE conditions; 例如: SELECT * FROM students WHERE name LIKE 'John%';INSERT INTO:用于向數(shù)據(jù)表中插入數(shù)據(jù),其語法格式為: INSERT INTO table_name (column1, column2, ...) VALUES (value1, value2, ...); 例如: INSERT INTO students (name, age, gender) VALUES ('Lucy', 20, 'female');UPDATE:用于更新數(shù)據(jù)表中已有的數(shù)據(jù),其語法格式為: UPDATE table_name SET column1=value1, column2=value2, ... WHERE conditions; 例如: UPDATE students SET name='Tom', age=22 WHERE id=3;DELETE FROM:用于刪除數(shù)據(jù)表中的數(shù)據(jù),其語法格式為: DELETE FROM table_name WHERE conditions; 例如: DELETE FROM students WHERE name='Lucy';
以上是MySQL的一些常用關(guān)鍵字及其用法,可以在實(shí)際應(yīng)用中靈活運(yùn)用。