TO_BOOLEAN
Purpose
Use TO_BOOLEAN to explicitly convert character value expressions or numeric value expressions to boolean values. 
                  
If expr is a string, it must evaluate to the allowed string inputs. See Table 2-6.
                  
expr can take one of the following types, or null:
                  
- 
                        
A character string of type
CHAR,VARCHAR2,NCHAR,NVARCHAR2 - 
                        
A numeric value of type
NUMBER,BINARY_FLOAT, orBINARY_DOUBLE - 
                        
A boolean value of type
BOOLEAN. 
Examples
SELECT TO_BOOLEAN(0), TO_BOOLEAN('true'), TO_BOOLEAN('no');The output is:
TO_BOOLEAN( TO_BOOLEAN( TO_BOOLEAN( ----------- ----------- ----------- FALSE TRUE FALSE
SELECT TO_BOOLEAN(1) FROM DUAL;
The output is:
TO_BOOLEAN( ----------- TRUE
See Also:
- 
                           
CAST for conversion rules.
 - 
                           
Boolean Data Type for more details on the built-in boolean data type.
 
