Must know facts

Question 1

Normalization?

How Does It Work

Answer 1

the process of designing database tables to minimize the data redundancy

divide a database into two or more tables and define relationships between them.

Use having only with group by clauses

Question 2

INNER JOIN

Answer 2

returns all the rows for which there is at least one match in BOTH the tables.

Question 3

LEFT JOIN

Answer 3

Returns all rows from the left table, and the matching rows from the right table.

Question 4

When does the where clause filter data?

When does the having clause filter data?

Answer 4

Before the data has been grouped

After the data has been grouped

Question 5

Facts about the primary key

Answer 5

Cannot be null

Every table can only have one primary key

Can be related to another table as a foreign key

Question 6

Facts about unique key

Answer 6

May have a null value

Table can have more than one unique constraint

Not related to another table as a foreign key

Question 7

What does sql stand for

Answer 7

Structured query language