VIEW

A VIEW is not a physical table, but rather, it is VIEW is a virtual table. If he VIEW already exists, the CREATE VIEW statement will return an error.

Why views?

• Views can be effective copies of base tables.
• Views can have column names and expressions.
• You can use any clauses in views.
• Views can be used in INSERT/UPDATE/DELETE.
• Views can contain expressions in the select list.
• Views can be views of views.

Restrictions on the View definition

• The SELECT statement cannot contain a subquery in the FROM clause.
• The SELECT statement cannot refer to system or user variables.
• Within a stored program, the definition cannot refer to program parameters or local variables.
• The SELECT statement cannot refer to prepared statement parameters.
• Any table or view referred to in the definition must exist.
• The definition cannot refer to a TEMPORARY table, and you cannot create a TEMPORARY view.
• Any tables named in the view definition must exist at definition time.
• You cannot associate a trigger with a view.
• Aliases for column names in the SELECT statement are checked against the maximum column length of 64 characters (not the maximum alias length of 256 characters).

Basic syntex:

CREATE VIEW View_Name AS SELECT * FROM Table_Name ;

Syntax For MySQL:

CREATE VIEW dept AS SELECT * FROM department;

After Execution: 
(0 row(s) affected)
(0 ms taken)

You can check created VIEW table by using these Syntex:

show tables

Result:

Tables_in_DB_Name

Table1

Table2

Table3

Table4

dept