It's a common request to get a list of people whose birthday (or an anniversary date) falls in the specified date range w/o regard to the year.
T-SQL has CHARINDEX and PATINDEX functions that return the position of one character expression in another. The ufn_AT and ufn_RAT functions add the ability to search for specified occurrences and to search from right to left.
The ufn_Mlines() UDF for SQL Server is similar to the VFP Mline() function but w/o third parameter.
It's more an example than finished UDF. I didn't do much testing on it.
The built-in SQL Server ISNUMERIC() function determines if character expression can be converted to one of the numeric types. The ufn_IsNumericEx() function accepts the second parameter - the data type to convert to and checks also for characters illegal for that data type. It doesn't check if the numeric value is in the range for specified data type though.
The ufn_StrExtract() UDF for SQL Server is similar to the VFP StrExtract() function.
The ufn_Proper() UDF for SQL Server is similar to the VFP Proper() function. It additionally allows to specify a set of delimiters.
The ufn_Alines() UDF for SQL Server is similar to the VFP Alines() function but w/o additional parameters.