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;
Filtering of Numeric Values
The where command can be used to filter numeric records. The following query selects all details for films with a budget over ten thousand dollars: SELECT * FROM films WHERE budget > 10000;