Which of the following is not a valid SQL statement?<\/p>\n\n\n\n
a. SELECT MIN(pubdate)<\/p>\n\n\n\n
FROM books<\/p>\n\n\n\n
GROUP BY category<\/p>\n\n\n\n
HAVING pubid = 4;<\/p>\n\n\n\n
b. SELECT MIN(pubdate)<\/p>\n\n\n\n
FROM books<\/p>\n\n\n\n
WHERE category = ‘COOKING’;<\/p>\n\n\n\n
c. SELECT COUNT(*)<\/p>\n\n\n\n
FROM orders<\/p>\n\n\n\n
WHERE customer# = 1005;<\/p>\n\n\n\n
d. SELECT MAX(COUNT(customer#))<\/p>\n\n\n\n
FROM orders<\/p>\n\n\n\n
GROUP BY customer#;<\/p>\n\n\n\n
The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n The correct answer is:<\/p>\n\n\n\n d. SELECT MAX(COUNT(customer#)) FROM orders GROUP BY customer#;<\/strong><\/p>\n\n\n\n Let’s break down why option d<\/strong> is invalid and why the others are valid.<\/p>\n\n\n\n In summary, the error in option d<\/strong> is that it incorrectly attempts to nest two aggregation functions ( Which of the following is not a valid SQL statement? a. SELECT MIN(pubdate) FROM books GROUP BY category HAVING pubid = 4; b. SELECT MIN(pubdate) FROM books WHERE category = ‘COOKING’; c. SELECT COUNT(*) FROM orders WHERE customer# = 1005; d. SELECT MAX(COUNT(customer#)) FROM orders GROUP BY customer#; The Correct Answer and Explanation is : […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-189486","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/189486","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=189486"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/189486\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=189486"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=189486"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=189486"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Explanation:<\/h3>\n\n\n\n
\n
SELECT MIN(pubdate) FROM books GROUP BY category HAVING pubid = 4;<\/code><\/strong><\/li>\n<\/ol>\n\n\n\n\n
GROUP BY<\/code> is used to aggregate rows based on the category<\/code> column, and MIN(pubdate)<\/code> is applied to find the minimum publication date for each category.<\/li>\n\n\n\nHAVING<\/code> clause is used to filter the results after aggregation. Here, it correctly filters the result to show only groups where pubid = 4<\/code>.<\/li>\n<\/ul>\n\n\n\n\n
SELECT MIN(pubdate) FROM books WHERE category = 'COOKING';<\/code><\/strong><\/li>\n<\/ol>\n\n\n\n\n
WHERE<\/code> clause filters the rows where the category<\/code> is ‘COOKING’.<\/li>\n\n\n\nMIN(pubdate)<\/code> finds the earliest publication date among the filtered rows. This is syntactically correct.<\/li>\n<\/ul>\n\n\n\n\n
SELECT COUNT(*) FROM orders WHERE customer# = 1005;<\/code><\/strong><\/li>\n<\/ol>\n\n\n\n\n
COUNT(*)<\/code> function counts the number of rows that match the condition customer# = 1005<\/code> in the orders<\/code> table. It is a common and correct usage of the COUNT<\/code> function.<\/li>\n<\/ul>\n\n\n\n\n
SELECT MAX(COUNT(customer#)) FROM orders GROUP BY customer#;<\/code><\/strong><\/li>\n<\/ol>\n\n\n\n\n
COUNT(customer#)<\/code> is an aggregate function that counts the number of orders for each customer#<\/code>, and GROUP BY customer#<\/code> groups the rows by customer. However, the MAX(COUNT(customer#))<\/code> syntax is invalid because the COUNT(customer#)<\/code> is already an aggregated value.<\/li>\n\n\n\nMAX(COUNT(...))<\/code>. If you want the maximum count of orders for a customer, you should first apply the COUNT<\/code> function with GROUP BY<\/code> and then apply MAX<\/code> to the result of that aggregation. The correct query would be:sql SELECT MAX(order_count) FROM (SELECT COUNT(customer#) AS order_count FROM orders GROUP BY customer#) AS subquery;<\/code><\/li>\n<\/ul>\n\n\n\nMAX<\/code> and COUNT<\/code>) in a way that is not allowed in SQL syntax.<\/p>\n","protected":false},"excerpt":{"rendered":"