SQL - Session 6

Will a Cartesian product of A x B have the same result as the Cartesian product B x A?

• Yes

• No

Will the following two queries produce the same result?

SELECT A.[name]

FROM A JOIN B ON A.FK = B.PK

WHERE B.[name] LIKE '%a%';

SELECT A.[name]

FROM A, B

WHERE A.FK = B.PK AND B.[name] LIKE '%a%';

• yes

• no

Will the following two queries produce the same result?

SELECT A.[name]

FROM A JOIN B ON A.FK = B.PK

WHERE B.[name] LIKE '%a%';

SELECT [name]

FROM A

WHERE FK IN (SELECT PK

FROM B

WHERE [name] LIKE '%a%');

• yes

• no

Although all three produce the same result, which should be used?

• The version with two tables in FROM

• The version with a subquery in WHERE

• The version that uses JOIN

The JOIN condition usually is....

• primary key to primary key

• foreign key to primary key

• foreign key to foreign key

Filtering groups is done using?

• SELECT

• GROUP BY

• HAVING

• FILTER

Can aggregation functions be used in a HAVING?

• yes

• no

When using a GROUP BY, what can be placed in the SELECT?

• any field from the table(s) used in FROM

• only fields that are grouped by

• only aggregation functions

• only fields that are grouped by and aggregation functions

To remove the content of a table, which SQL clause needs to be used?

• DROP TABLE

• DELETE FROM

• REMOVE

• CLEAN

ALTER TABLE is part of SQL's....

• DML

• DDL

• DAL

• DCL