In SQL, which character is used to select all columns from a table?

The asterisk (*) is the correct character used in SQL to select all columns from a table. When constructing a SQL query, using the asterisk allows you to retrieve every column's data from the specified table without having to list each column individually. This is particularly useful for quickly pulling and displaying all the available data, especially in tables with numerous columns.

For example, a typical SQL command to select all columns from a table named "employees" would look like this:

SELECT * FROM employees;

This command effectively retrieves all rows and columns from the "employees" table, which can be very handy for exploratory data analysis or when you need a quick overview of the table's contents.

In contrast, other characters like the plus sign, at symbol, or hash are not recognized in SQL syntax for this purpose, making them incorrect choices for this question.