A column heading in a select list can contain any character, even spaces or blanks, if the column heading is enclosed in single quotation marks ('). It can have a maximum of 30 characters. A column heading not enclosed in single quotation marks must conform to the rules for identifiers.
For example:
SELECT 'Book Publisher' = pub_name FROM publishers
The result is:
Book Publisher --------------------- New Moon Books Binnet & Hardley Algodata Infosystems Five Lakes Publishing Ramona Publishers GGG&G Scootney Books Lucerne Publishing (8 row(s) affected)
In addition, you can use Transact-SQL reserved words in quoted column headings. For example, the following query uses the reserved word SUM as a column heading:
SELECT 'sum' = SUM(ytd_sales) FROM titles
Note that you can use a quoted string for a column heading in a table definition (CREATE TABLE), or in SELECT INTO and CREATE VIEW statements only if the SET option QUOTED_IDENTIFIER is set to 'ON'. Otherwise, column headings in these statements must conform to the rules for identifiers.