Knowledge in mysql storage engines

MySQL Functions

MySQL Functions MySQL has many built-in functions. This reference contains string, numeric, date, and some advanced functions in MySQL. ________________________________________

SQL PRIMARY KEY Constraint

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 can have only ONE primary key; and in the table, this primary key can consist of single or multiple columns (fields).