Wednesday, January 25, 2012

Diff type of SELECT Command In sql

The SQL SELECT statement is used to select or fetch data from a SQL database table. This is usually the very first SQL command every SQL new person learns and this is because the SELECT SQL statement is one of the most used SQL commands.
Please have a look at the general SQL SELECT syntax and example:
Syntax:           SELECT Column1, Column2, Column3, FROM Table1
Database:       Adventure Works
Schema:          Person
Table:              Address
Query:            select AddressID,AddressLine1  from Person.Address

The list of column names after the SQL SELECT command determines which columns you want to be returned in your result set. If you want to select all columns from a database table, you can use the following SQL statement:

Database: Adventure Works
Schema: Person
Table: Address
Syntax:           SELECT * FROM Table1
Example:        select *  from Person.Address 
            select *  from Address 

When the list of columns following the SELECT SQL command is replaced with asterix (*) all table columns are returned. Word of caution here, it’s always better to explicitly specify the columns in the SELECT list, as this will improve your query performance significantly.
The table name following the SQL FROM keyword (in our case Table1) tells the SQL interpreter which table to use to retrieve the data.

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