SQL Common Statement Collection (constantly updated)

1. Multi-Criteria Enquiry subordinate All Data

SELECT * from Orgunit where (parentid = ' 3 ' or orgid= ' 3 "or ParentID in (select OrgId from Orgunit where parentid= ' 3 '))

2. of the same number of columns Multiple Query Results Combination (union All)

Select A,b,c from table1

UNION ALL

Select CA,CB,CC from Table2

3. Left outer connection with right outer connection (left jion, starboard jion)

The left JOIN keyword returns all rows from the table (TABLE_NAME1), even if there are no matching rows in the right table (table_name2).

　Now we want to list all the people as well as their orders-if any.

You can use the following SELECT statement:

SELECT Persons.lastname, Persons.firstname, Orders.orderno from Persons
   on ORDER by Persons.lastname

The right JOIN keyword returns all rows from the table (table_name2), even if there are no matching rows in the left table (table_name1).

Now, we want to list all the orders and the people who ordered them-if any.

You can use the following SELECT statement:

  SELECT Persons.lastname, Persons.firstname, Orders.orderno from  Persons right  JOIN Orders  on Persons.id_p=orders.id_p  ORDER by Persons.lastname