You can include any characters—including blanks—in a column heading if you enclose the entire heading in quotation marks.
You need not set the quoted_identifier option on. If the column heading is not enclosed in quotation marks, it must conform to the rules for identifiers. Both of these queries produce the same result:
select "Publisher's Name" = pub_name from publishers
select pub_name "Publisher's Name" from publishers
Publisher’s Name ---------------- New Age Books Binnet & Hardley Algodata Infosystems (3 rows affected)
select "sum" = sum(total_sales) from titles
Quoted column headings cannot be more than 255 bytes long.