The first SQL query most people learn is the SELECT statement with a query some thing like the following.
SELECT * FROM users WHERE id > 100
Nothing wrong with the syntax itself; but more often than not, what the user really wants is just a few columns from the table as shown in the PHP code below. Here we are only using three columns from the table. The usual practice of developers is to use the
* modifier to get all the columns from the table as it is easier then specifying individual column names. It is quicker to select all columns from a table and worry later which to actually use in the code.