The data type is a guideline for SQL to understand what type of data is expected inside of each column, and it also identifies how SQL will interact with the stored data. Note: Data types might have different names in different database.

SQL is a standard language for storing, manipulating and retrieving data in databases. Our SQL tutorial will teach you how to use SQL in: MySQL, SQL Server, MS Access, Oracle, Sybase, Informix, Postgres, and other database systems.

The data type is a guideline for SQL to understand what type of data is expected inside of each column, and it also identifies how SQL will interact with the stored data. In MySQL there are three main data types: string, numeric, and date and time.

What is SQL? SQL stands for Structured Query Language; SQL lets you access and manipulate databases; SQL became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standardization (ISO) in 1987

SQL ALTER TABLE Statement. The ALTER TABLE statement is used to add, delete, or modify columns in an existing table. The ALTER TABLE statement is also used to add and drop various constraints on an existing table.

Some of The Most Important SQL Commands. SELECT - extracts data from a database; UPDATE - updates data in a database; DELETE - deletes data from a database; INSERT INTO - inserts new data into a database; CREATE DATABASE - creates a new database; ALTER DATABASE - modifies a database; CREATE TABLE - creates a new table; ALTER TABLE - …

data_type: Required. The datatype to convert expression to. Can be one of the following: bigint, int, smallint, tinyint, bit, decimal, numeric, money, smallmoney, float, real, datetime, smalldatetime, char, varchar, text, nchar, nvarchar, ntext, binary, varbinary, or image (length) Optional.

Changes the data type of a column or deletes a column in a table: CONSTRAINT: Adds or deletes a constraint: CREATE: Creates a database, index, view, table, or procedure: CREATE DATABASE: Creates a new SQL database: CREATE INDEX: Creates an index on a table (allows duplicate values) CREATE OR REPLACE VIEW: Updates a view: CREATE TABLE: Creates a ...

The data type specifies what type of data the column can hold. For a complete reference of all the data types available in MySQL, go to our complete Data Types reference . The "Persons" table will now look like this:

DATABASE: Returns the name of the current database: IF: Returns a value if a condition is TRUE, or another value if a condition is FALSE: IFNULL: Return a specified value if the expression is NULL, otherwise return the expression: ISNULL: Returns 1 or 0 depending on whether an expression is NULL: LAST_INSERT_ID