diff --git a/2208/天天乐学考试答案/MySQL练习(一).md b/2208/天天乐学考试答案/MySQL练习(一).md index 44839cb..5196944 100644 --- a/2208/天天乐学考试答案/MySQL练习(一).md +++ b/2208/天天乐学考试答案/MySQL练习(一).md @@ -230,13 +230,19 @@ FROM tb_books b; UPDATE tb_books b SET b.note = SUBSTR(b.note,INSTR(b.note,'-')+2); -#7 tj11 +#7 tj11 多表连接+条件+排序 SELECT b.book_id, b.title, a.author_id, a.author_name, b.publication_date FROM tb_books b, tb_authors a WHERE b.note = a.author_name AND YEAR(b.publication_date) BETWEEN 1980 AND 2010 ORDER BY b.publication_date DESC; -#8 +#8 tj12 多表连接+分组+分组后条件 +SELECT a.author_id, a.author_name, COUNT(*) +FROM tb_books b, tb_authors a +WHERE b.note = a.author_name +GROUP BY a.author_id +HAVING COUNT(*) > 1; + #9 ```