sql-select

Question 1

What is SQL and how is it different from languages like JavaScript?

Answer 1

SQL is the primary way of interacting with relational databases. It is a powerful way of retrieving, creating, and manipulating data in a relational database. Unlike JS which is an imperative language, SQL is a declarative language. In declarative languages, programmers describe the results they want and the programming environment comes up with its own plan for getting those results.

Question 2

How do you retrieve specific columns from a database table?

Answer 2

Use the keyword ‘select’ followed by a comma separated list of column names in double quotes. Use the keyword ‘from’ and type table name in double quotes. Always end with semi colon

Question 3

How do you filter rows based on some specific criteria?

Answer 3

‘where’

Question 4

What are the benefits of formatting your SQL?

Answer 4

It is just orderly. For readability.

Question 5

What are the four comparison operators that can be used in a ‘where’ clause?

Answer 5

The value of the ‘category’ column is being compared using a single = equals sign. (Other comparisons like , !, and = are available too)

Question 6

How do you limit the number of rows returned in a result set?

Answer 6

Use the ‘limit’ clause

Question 7

How do you retrieve all columns from a database table?

Answer 7

Use an asterisk *

Question 8

How do you control the sort order of a result set?

Answer 8

You can do ‘order by’