NVL vs Coalesce

• NVL is an Oracle Function. Hence works perfect in Oracle, may or may not work on other RDBMS softwares.
  
• Coalesce is an ASCII function. Hence works perfect on any RDBMS software.
  
• NVL can implicitly convert datatypes. But Coalesce cannot.
  
  
  Example:
  
  
  
  
  
  
   
• Syntaxes:    NVL (expr1, expr2 )
  
  Coalesce( expr1, expr2 )
  
• Coalesce executes faster than NVL. (~ 0.5 times ). This is because, NVL evaluates both the arguments and Coalesce evaluates only first argument.