Day 1

History

1

Who first proposed the relational model?

Edgar F. Codd

2

In what year was SQL first developed at IBM?

1974

3

Who was the client of Oracle Version 1?

CIA

4

What was the first version of Oracle officially released?

Version 2

5

Who were the first three software engineers that founded Software Development Laboratories?

Larry Ellison, Bob Miner, and Ed Oates

Select

1

How do you select unique records only? 

Using the Distinct keyword

2

What is the syntax for the basic SELECT clause to get all rows?

SELECT *

3

What is the template for SELECT statements?

SELECT [DISTINCT] *|{_column_|expression [alias],…} FROM _table_;

4

When an expression is returned as a column, what appears as the column name?

The expression itself

5

How do you select unique records by multiple columns (e.g. by job and department id)?

DISTINCT(col1, col2, ..., coln)

Filtering

1

What statement is used to define the conditions tofilter the results by

WHERE

2

What statement is used to check for null

ISNULL

3

The between statement is inclusive of the start and end? True or False

True

4

What is the symbol used to represent wildcards for single characters for the LIKE keyword.

_ (underscore)

5

What is the difference between Where and Having

Where is for regular columns, having is for aggregated columns

Relational Database

1

A relational database stores data as ____

a set of simple relations/as a table of row and columns

2

A row in a relation is referred to as a ___

tuples or records

3

True or false, SQL code is completely portable between different database systems 

False

4

SQL adheres to a set standard. True or False

True

5

SQL consists of what 3 languages?

DDL, DML, DCL

Single Row Functions

1

What function do we use to perform exponentiation

POWER

2

Suppose we want to compare two strings in a case insensitive manner, what function/s can we use to ensure this works as expected?

UPPER() or LOWER()

3

We have a column called counter and we want it to display the numbers in a fixed number of digits. What function should we use to achieve this? 

LPAD()

4

Suppose we have a column for first_name and last_name, how can we display this as a column for full name using single row functions

CONCAT(first_name, " ", last_name)

5

What is the where clause of the SQL statement to filter rows for employees that started within the past 30 days? Assume start_date is the column for the starting date of the employee.

WHERE start_date > CURRENT_DATE() - 30