一、原题 View the Exhibit and examine the data in the PROMOTIONS table. You need to display all promo categories that do not have discount in their subcategory. Which two SQL statements give the required result? (Choose two.) A. SELECT promo_category …

一、原题 Which statement is true regarding the INTERSECT operator?A. It ignores NULL values.B. Reversing the order of the intersected tables alters the result.C. The names of columns in all SELECT statements must be identical.D. The number of columns and…

最近几年，MySQL 不断致力于兼容 SQL 标准。例如 MySQL 8.0 中的窗口函数、通用表表达式、检查约束等等。 最新发布的 MySQL 8.0.31 继续对 SQL 语句进行了增强，提供了缺失已久的两个集合操作符：INTERSECT 和 EXCEPT。 交集操作符&#xff0…

一、原题 View the Exhibits and examine the structures of the PRODUCTS and SALES tables. Which two SQL statements would give the same output? (Choose two.) A. SELECT prod_id FROM products INTERSECT SELECT prod_id FROM sales; B. SELECT prod_id …

一、原题 View the Exhibit and evaluate structures of the SALES, PRODUCTS, and COSTS tables. Evaluate the following SQL statement: SQL>SELECT prod_id FROM products INTERSECT SELECT prod_id FROM sales MINUS SELECT p…

1、UNION和UNION ALL的使用与区别 如果我们需要将两个select语句的结果作为一个整体显示出来，我们就需要用到union或者union all关键字。union的作用是将多个结果合并在一起显示出来。 union和union all的区别是union会自动压缩多个结果集合中的重复结果&#xff…

一、原题 View the Exhibit and examine the structure of the CUSTOMERS and CUST_HISTORY tables. The CUSTOMERS table contains the current location of all currently active customers. The CUST_HISTORY table stores historical details relating to any changes in…