To select multiple columns in SQL, you can provide a comma-separated list of column names after the SELECT keyword. Here’s an example:

SELECT column1, column2, column3
FROM table_name;

In the above example, column1, column2, and column3 are the names of the columns you want to select. table_name represents the table from which you want to retrieve the data.

You can also use the asterisk (*) symbol to select all columns in a table, like this:

SELECT *
FROM table_name;

However, using the asterisk is not considered a best practice, especially in larger databases or when working with complex queries. It is recommended to explicitly specify the columns you need in your SELECT statement to improve query performance and reduce the amount of data retrieved.

If you want to give a specific name to the columns in the result set, you can use aliases. Aliases are useful when you want to provide more meaningful or shorter names to the columns. Here’s an example:

SELECT column1 AS alias1, column2 AS alias2
FROM table_name;

In the above example, column1 will be referred to as alias1 in the result set, and column2 will be referred to as alias2.

To add search conditions or apply filters to the SELECT statement, you can use the WHERE clause. For example:

SELECT column1, column2
FROM table_name
WHERE condition;

In the above example, you can replace condition with any valid expression that filters the rows based on certain criteria.

To summarize, selecting multiple columns in SQL is done by specifying the column names after the SELECT statement. It is considered a best practice to explicitly list the required columns instead of using the asterisk. Additionally, aliases can be used to provide more meaningful names to the columns in the result set.