AJAX – Send a Request To a Server The XMLHttpRequest object is used to exchange data with a server. Send
JSON PHP A common use of JSON is to read data from a web server, and display the data in
SQL NULL Values What is a NULL Value? A field with a NULL value is a field with no value.
SQL Self JOIN SQL Self JOIN A self JOIN is a regular join, but the table is joined with itself.
SQL CREATE TABLE Statement The SQL CREATE TABLE Statement The CREATE TABLE statement is used to create a new table
SQL Data Types for MySQL, SQL Server, and MS Access The data type of a column defines what value the
SQL COLUMN Keyword ALTER COLUMN The ALTER COLUMN command is used to change the data type of a column in
SQL DROP COLUMN Keyword DROP COLUMN The DROP COLUMN command is used to delete a column in an existing table.
SQL INNER JOIN Keyword INNER JOIN The INNER JOIN command returns rows that have matching values in both tables. The