Querying a Database: The SELECT statement

In this video we learn about writing queries involving a single table.

files used in this video

To follow along, you will need to download and install 2 sql files:

Basic Query Patterns

Simple WHERE clause
SELECT <columns> FROM <table> WHERE <condition>;
SELECT * FROM books WHERE author = 'Ann Mulkern';
SELECT author, title FROM books WHERE publisher = 'Wisdom';
SELECT movie FROM movies WHERE tomatorating > 90;
and / or
SELECT <columns> FROM <table> WHERE <condition>;
<condition> = <columnName> = <value>
<condition> = <condition> AND <condition>
<condition> = <condition> OR <condition>
SELECT movie FROM tomato WHERE firstname = 'Anne' AND lastname = 'Hathaway';
SELECT DISTINCT <columns> FROM <table> WHERE <condition>;
SELECT DISTINCT firstname, lastname from tomato;
LIKE / ILIKE and the wildcard %
<condition> = <columnName> LIKE <value>
<condition> = <columnName> ILIKE <value>    *case insensitive* 
SELECT movie FROM tomato WHERE movie LIKE 'S%';
SELECT movie FROM tomato WHERE movie ILIKE '%avenger%';


Pattern Description
A% matches any string that start with an ‘A’
%ed matches any string that ends with ‘ed’
A%ed matches any string that starts with ‘A’ and ends with ‘ed’
%z% matc hes any string that contains a ‘z’ (can start with, end with, or contain a z)
<condition> = <columnName> IS NULL
<condition> = <columnName> IS NOT NULL
SELECT movie FROM tomato where release-date IS NULL;
SELECT <columns> FROM <table> WHERE <condition> ORDER BY <columnNames>;
SELECT movie FROM tomato ORDER BY movie;
SELECT firstname, lastname FROM tomato WHERE movie = 'Avengers' ORDER BY lastname, firstname;

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