Two ways to use MySQL in

Briefly describe the two usages of MySQL in:

They are followed by a table (recordset) in the In keyword, and a string set after in.

Let's go ahead and follow a table.

First, the structure of three tables is elaborated:

S (sno,sname.sex,age,dept)//Student Information Sheet

C (cno,cname,tname)//Course Information Sheet

SC (Sno,cno,grade)//course Elective Information sheet

Update SC Set grade = 0 where sc.cno in (select CNO from c where c.cname = ' physical ') and Sc.grade < 60; For example, this SQL statement, which is a 0-point set of failed scores for a course, is a physical one.

In this example, the in is followed by a temporary table generated by the SELECT statement.

OK, now look at the following in followed by a string set, it is not necessarily a string set.

SELECT * from S where sname in (' AAA ', ' BBB ', ' CCC ');

Two ways to use MySQL in