No, in SQL injection you use UNION SELECT statements to try to find the number of columns the website has.
For example,
vulnerablewebsite.com/vulnerable.php?vulnerableURL=UNION SELECT 7--
If there's 7 columns or under, it would return a normal page.
If you do
vulnerablewebsite.com/vulnerable.php?vulnerableURL=UNION SELECT 8--
and there's only 7 columns, there would be a huge MySQL error covering that page, about how it can't read the 8th column.
EDIT: GOD DANG IT, IT WON'T UN-HYPERLINK IT. Gonna remove the www.
Lel. This isn't right. Union simply merges multiple select queries, but it will only work if the resulting queries return the same number of columns. In MySQL, SELECT 7 will, like Charles said, return one column, one row, with a header and value of 7. So if you had a table with 7 columns, and you tried to perform a union with SELECT 7, it would give a MySQL error (which may or may not be reflected in your page).
If you truly wanted to test how many columns there were in a
table with a union, you'd want to do something like UNION SELECT 1,2,3,4,5,6,7 for 7 columns.
rk, it was more for the humor of putting an SQL statement as the value more than it was to actually try to exploit it. And anyway, I would have had to post a huge number that I would expect to dump an error, because the LG database probably has way more than 7 measly columns.