SQL PRIMARY KEY Constraint - W3Schools.com
SQL PRIMARY KEY Constraint The PRIMARY KEY constraint uniquely identifies each record in a table. Primary keys must contain UNIQUE values, and cannot contain NULL values. A table …
MySQL PRIMARY KEY Constraint - W3Schools
MySQL PRIMARY KEY Constraint The PRIMARY KEY constraint uniquely identifies each record in a table. Primary keys must contain UNIQUE values, and cannot contain NULL values. A …
SQL FOREIGN KEY Constraint - W3Schools
The FOREIGN KEY constraint is used to prevent actions that would destroy links between tables. A FOREIGN KEY is a field (or collection of fields) in one table, that refers to the PRIMARY …
W3Schools SQL Exercise
You completed the SQL Primary Key Exercises from W3Schools.comI completed a SQL exercise on w3schools.com
SQL Keywords Reference - W3Schools
This SQL keywords reference contains the reserved words in SQL.
MySQL SQL - W3Schools
What is SQL? SQL is the standard language for dealing with Relational Databases. SQL is used to insert, search, update, and delete database records.
MySQL ALTER TABLE Statement - W3Schools
ALTER TABLE - MODIFY COLUMN To change the data type of a column in a table, use the following syntax:
Python MySQL Create Table - W3Schools
Primary Key When creating a table, you should also create a column with a unique key for each record. This can be done by defining a PRIMARY KEY. We use the statement "INT …
SQL INNER JOIN - W3Schools
JOIN Three Tables The following SQL statement selects all orders with customer and shipper information: Here is the Shippers table:
SQL ORDER BY Keyword - W3Schools
The SQL ORDER BY The ORDER BY keyword is used to sort the result-set in ascending or descending order.