摘苹果

摘要： 数据分组：select column_name count(*) as new_name from table_name group by column_name 分组语法 having count(*)>= 100; 筛选组别语法 输入▼ SELECT vend_id, COUNT(*) AS n 阅读全文

摘要： 修改表列名：alter table table_name change column old_column_name new_column_name the_type_of_date ; sql聚集函数：select avg(`column_name`) as avg_column_name fro 阅读全文