Sams Teach Yourself SQL in 24 Hours, Second Edition

The Concept of Combining Character Functions

Most functions can be combined in a single SQL statement. SQL would be far too limited if function combinations were not allowed. The following examples show how some functions can be combined with one another in a query:

						SELECT LAST_NAME || ', ' || FIRST_NAME NAME,
						SUBSTR(EMP_ID,1,3) || '-' ||
						SUBSTR(EMP_ID,4,2) || '-' ||
						SUBSTR(EMP_ID,6,4) ID
						FROM EMPLOYEE_TBL;
					

NAME               ID
------------------ -----------
STEPHENS, TINA     311-54-9902
PLEW, LINDA        442-34-6889
GLASS, BRANDON     213-76-4555
GLASS, JACOB       313-78-2439
WALLACE, MARIAH    220-98-4332
SPURGEON, TIFFANY  443-67-9012

6 rows selected.

The following example combines two functions in the query (concatenation with substring). By pulling the EMP_ID column ...