Returns 1 if the Unicode value at start is the low half of a surrogate pair (which should appear second in the pair). Otherwise, returns 0. This function allows you to explicitly code around the adjustments performed by substr(), stuff(), and right().
ulowsurr(uchar_expr, start)
is a character-type column name, variable, or constant expression of unichar or univarchar type.
specifies the character position to investigate.
ulowsurr, a string function, allows you to write explicit code around adjustments performed by substr, stuff, and right. Specifically, if a substring ends on a Unicode value where ulowsurr is true, the user knows to extract a substring of 1 less characters (or 1 more). substr does not extract a string that contains an unmatched surrogate pair.
If uchar_expr is NULL, ulowsurr returns NULL.
ANSI SQL – Compliance level: Transact-SQL extension.
Any user can execute ulowsurr.
Documentation Transact-SQL Users Guide
Function uhighsurr