請問哪一個 SQL 陳述式會傳回訂單數目少於50 的國家/地區以及各國家/地區的訂單數目? orderID 代表個別訂單、Country 代表國家/地區,而 Orders 代表訂單數目。 A. SELECT Country, orderID FROM Orders WHERE COUNT (orderID) < 50; GROUP BY Country: B. SELECT COUNT (orderID). Country FROM Orders HAVING COUNT (orderID) < 50; GROUP BY Country C. SELECT Country, orderID GROUP BY Country WHERE COUNT (orderID) < 50: FROM Orders D. SELECT COUNT (orderID), Country FROM Orders GROUP BY Country HAVING COUNT (orderID) < 50;

Which SQL statement returns countries with fewer than 50 orders and the number of orders for each country? orderID represents individual orders, Country represents countries, and Orders represents the number of orders. A. SELECT Country, orderID FROM Orders WHERE COUNT (orderID) < 50; GROUP BY Country: B. SELECT COUNT (orderID). Country FROM Orders HAVING COUNT (orderID) < 50; GROUP BY Country C. SELECT Country, orderID GROUP BY Country WHERE COUNT (orderID) < 50: FROM Orders D. SELECT COUNT (orderID), Country FROM Orders GROUP BY Country HAVING COUNT (orderID) < 50;

HAVING Syntax

SELECT *column_name(s)*FROM table_nameWHERE conditionGROUP BY *column_name(s)*HAVING conditionORDER BY column_name(s);

SQL HAVING Clause

SQL GROUP BY Statement

分析文法: "Which SQL statement returns countries?" 這個句子是一個疑問句，包含一個獨立從句。該從句的主語是 "Which SQL statement"，謂語是 "returns"。

謂語的賓語是 "countries"，是一個名詞短語，作為該從句的直接賓語。

總體而言，這個句子是一個簡單句，包含一個疑問詞和一個動詞，用於詢問一個 SQL 語句，該語句返回哪些國家的信息

一般用法｜解析 which「哪一個」用法及中文含義

which 一般最常見的用法為疑問形容詞，中文意思是「哪個、哪一個」，意指當選項是固定數目時，詢問對方要挑選哪一個，以下方3個句子為例，可以看出 which 後面為名詞，若無介係詞，則接單數名詞，如果是從眾多數量中挑選，則 which 需搭配 of 才能放上複數名詞。