Returns the starting position of the specified occurrence of searchString in text.
text - any text expression or text field
searchString - any text expression or text field representing the set of characters you want to find.
start - any numeric expression, or field containing a number, representing the number of characters from the start of the text string at which to begin the search.
occurrence - any numeric expression or field containing a number, representing which instance of the text string you want to find. A negative occurrence value causes the scan to go in the opposite direction from start. A zero value for occurrence is invalid and returns a result of zero.
Data type returned 
Originated in 
FileMaker Pro 6.0 or earlier
This function is not case-sensitive. If searchString isn’t contained in text or if there was no specified occurrence, zero is returned.
Position(“Mississippi”;“iss”;1;1) returns 2.
Position(“Mississippi”;“iss”;1;2) returns 5.
Position(“Mississippi”;“iss”;3;1) returns 5.
Left(Name;Position(Name;“ “;1;1)-1) returns William, when Name is a text field that contains William Smith.
Right(Name;Length(Name) - Position(Name;“ “;Length(Name);-1)) returns Smith.
Related topics 
Functions reference (category list)
Functions reference (alphabetical list)
About formulas
About functions
Defining calculation fields
Using operators in formulas