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Retrieving Columns from a Database Table in SQL

by Ron Kurtus (3 February 2007)

You can use SQL to retrieve the columns of a database table with the SELECT statement. You can retrieve all columns, a single column, or several specific columns. It is then up to your programming language to display that data.

Questions you may have include:

• How do you retrieve all columns?
• How do you retrieve a single columns?
• How do you retrieve selected columns?

This lesson will answer those questions. There is a mini-quiz near the end of the lesson.

All columns

You can query a database to retrieve all the elements in a database table by using the SELECT statement and wildcard (*) indicator.

SELECT *
FROM table_name;

Note: It is standard practice to add ";" at the end of your SQL query. Some databases require it and some don't.

Single column

The most common query from a database is to collect or retrieve all the elements in a specific column of the database table.

SELECT column_name
FROM table_name;

Several select columns

You can also retrieve data from several columns by separating the column names with a comma.

SELECT column_1, column_2, column_7
FROM table_name;

Note: Do not place a comma after the last item in the list, because it will result in an error message.

Summary

The SELECT statement is used to retrieve the columns of a database table. You can retrieve all columns, a single column, or several specific columns.

Answers to Readers' Questions

Resources

The following are resources on this subject.

Websites

SQL Resources

Books

Top-rated books on SQL

Miscellaneous

Mini-quiz to check your understanding

1. What is a "wildcard" symbol mean?

2. Why is ";" used after the table name?

3. Does the order you list the columns matter?

If you got all three correct, you are on your way to becoming a Champion in working with SQL. If you had problems, you had better look over the material again.

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Retrieving Columns from a Database Table in SQL