SQL Cookbook: Inserting, updating, and deleting

1. Copy rows from one table to another

1  into dept_east (Deptno, Dname, loc) 2 Select deptno, dname, loc 3  from Dept 4 where inch ('New York'Boston')

2. Duplicate table structure

Changing the Where condition can also copy part of the data

1 mysql>createtableas2-     Select  *from  film3,     where1 = 0\g

3. Block insertions to a few columns

Create a view that displays only the columns that the user is allowed to access

4. Delete all records from the table

Delete Does not take where to

5, the meaning of group by is equivalent to selecting columns with the same column values for merging, generally with the aggregate function

1 Select  from Group  by  having Count (*>=2

SQL Cookbook: Inserting, updating, and deleting