TOBOOLEAN Function

Parameters: (String value)

Returns: Boolean {or NULL};

Returns TRUE if the string value is a recognised boolean 'TRUE' value (True, Yes) or FALSE if it is a recognised FALSE value (False, No)

Returns NULL if the string value is not a recognised boolean value.

The parameter is the value to be checked to see which Boolean value it represents

Examples:

Example 1: TOBOOLEAN('TRUE') = TRUE

Example 2:  TOBOOLEAN('no') = FALSE

Example 3: TOBOOLEAN('hello') = NULL

Example 4: TOBOOLEAN(NULL) = NULL