SQL Commands

Below I have listed the most common commands that I am using when acquiring data from a database

Selecting a single Column from a table:

This will select the column "Name" from the "People" Table.
SELECT name 
FROM people; 

Selecting multiple columns from a table:

This will select the Name and Birthrate column from the people table.
SELECT name, birthdate
FROM people; 

This will select all columns from a table.
SELECT *
FROM people; 

This will select 10 rows with all columns from a table. 
SELECT *
FROM people
LIMIT 10; 

This will select 10 rows with all columns from a table.
SELECT *
FROM people
LIMIT 10; 

Selecting all unique values from a column:

This will select all the unique values in the language column from the films Table.
SELECT DISTINCT language
FROM films;

Counting in a table:

This will count all the rows in the people table.
SELECT COUNT(*)
FROM people;


Placing a column in the count command will count all the non missing values.
This will count the number of birth dates present in the people table
SELECT COUNT(birthdate)
FROM people;


To count the number of distinct values, the following can be used
SELECT COUNT(DISTINCT birthdate)
FROM people;