I have a table with lots of columns and from that table I've selected 2 columns of data which can be seen below.

The 2 columns are:
user_email and letter

user_email contains every person's email address and letter column contains a value which is either A or B. Each person's email can appear in any number of rows.

example: table_X
Code:
bob@hotmail.com, B
bob@hotmail.com, B
bob@hotmail.com, A
chris@hotmail.com, A
chris@hotmail.com, A
sue@hotmail.com, B
jess@yahoo.com, A
jess@yahoo.com, A
jess@yahoo.com, A
jess@yahoo.com, B
I'm trying to find out 3 different values, the number of users (I assume using COUNT) who:
  1. Have both A and B
  2. Have Only B
  3. Have Only A

This one's stumped me. Any ideas?