You can use a combiation of LEFT
and CHARINDEX
to find the index of the first space, and then grab everything to the left of that.
SELECT LEFT(YourColumn, charindex(' ', YourColumn) - 1)
And in case any of your columns don't have a space in them:
SELECT LEFT(YourColumn, CASE WHEN charindex(' ', YourColumn) = 0 THEN
LEN(YourColumn) ELSE charindex(' ', YourColumn) - 1 END)