Diference Between & and && in SQL

[krishnaindia2007]

what is the difference between & and && in sql ?
Ex:- 1. spool &filename
2. CONNECT &&USER/&&PASSWORD@&&DBSERVER;

What is the use of these two operators?


Regards
Krishna

[susarlasireesha]

"&" is used to create a temporary substitution variable that will prompt you for a value every time it is referenced.

"&&" is used to create a permanent substitution variable. Once you have entered a value (defined the variable) its value will used every time the variable is referenced.

[debasisdas]

That is used so that the user don't have to enter value of the variable repeatedly, in case the variable is processed more than once in the program.