联用的意思是不是出现在同一语句中?
1.select在update语句的where中
UPDATE titles
SET ytd_sales = titles.ytd_sales + sales.qty
FROM titles, sales
WHERE titles.title_id = sales.title_id
AND sales.ord_date = (SELECT MAX(sales.ord_date) from sales)
2.select在update语句的set中
UPDATE titles
SET ytd_sales =
(SELECT SUM(qty)
FROM sales
WHERE sales.title_id = titles.title_id
AND sales.ord_date IN (SELECT MAX(ord_date) FROM sales))
FROM titles, sales
3.select在update语句的from中
UPDATE authors
SET state = 'ZZ'
FROM (SELECT TOP 10 * FROM authors ORDER BY au_lname) AS t1
WHERE authors.au_id = t1.au_id
