Interactive SQL Tutorial

2. Basics of the SELECT Statement

In a relational database, data is stored in tables. An example table would relate Social Security Number, Name, and Address:

Employee Address Table
SSN	FirstName	LastName	Address	City	State
512687458	Joe	Smith	83 First Street	Howard	Ohio
758420012	Mary	Scott	842 Vine Ave.	Losantiville	Ohio
102254896	Sam	Jones	33 Elm St.	Paris	New York
876512563	Sarah	Ackerman	440 U.S. 110	Upton	Michigan

Now, let's say you want to see the address of each employee. Use the SELECT statement, like so:

SELECT FirstName, LastName, Address, City, State

FROM EmployeeAddressTable

The following is the results of your query of the database:

First Name	Last Name	Address	City	State
Joe	Smith	83 First Street	Howard	Ohio
Mary	Scott	842 Vine Ave.	Losantiville	Ohio
Sam	Jones	33 Elm St.	Paris	New York
Sarah	Ackerman	440 U.S. 110	Upton	Michigan

To explain what you just did, you asked for the all of data in the EmployeeAddressTable, and specifically, you asked for the columns called FirstName, LastName, Address, City, and State. Note that column names and table names do not have spaces...they must be typed as one word. The general form for a SELECT statement, retrieving all of the rows in the table is:

SELECT ColumnName, ColumnName, ...

FROM TableName

To get all columns of a table without typing all column names, use:

SELECT * FROM TableName

Each database management system (DBMS) and database software has different methods for logging in to the database and entering SQL commands; see the local computer "guru" to help you get onto the system, so that you can use SQL.

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