count the number of spaces in values in sql server

This will give a different and more accurate result than the other answers, it is also counting spaces in the end of the words, it becomes clear when tested on these examples:

DECLARE @a table(column1 varchar(20))
INSERT @a values('b c ')
INSERT @a values('b c')
INSERT @a values('   b c      ')

SELECT 
LEN(column1 + ';')-LEN(REPLACE(column1,' ','')) - 1 accurate,
LEN(column1)-LEN(REPLACE(column1,' ', '')) [inaccurate] -- other answers
FROM @a

Result:

accurate    inaccurate
2           1
1           1
10          4

SELECT LEN(column1)-LEN(REPLACE(column1, ' ', '')) FROM YourTableName