a saxophone (learn to spell) has no flat keys. There are different keys for each note. There is no individual key for a flat
An alto saxophone is in the key of E-Flat, or Eb
The most popular members of the saxophone family are the soprano, alto, tenor and baritone saxophone. The soprano is based in the key of B-flat, the alto E-flat, the tenor B-flat and the baritone E-flat. There have been other variations of the saxophone as well, including the sopranino (e-flat), bass (b-flat) contra bass (e-flat) and c melody saxophone.
The Alto Saxophone is in the key of E flat. That means that an E flat on the Alto Saxophone is the same pitch as a C on a piano or other concert pitch instrument.
Some E-flat instruments include the alto clarinet, sopranino saxophone, alto saxophone, baritone saxophone, contralto clarinet, and the tenor horn. There is even an E-flat tuba, but it's not regularly used.
g sharp
The B-flat soprano saxophone is in the same key as the common B-flat soprano clarinet. In other words, the sounding pitches on their respective music would be the same. The clarinet and saxophone families both have many instruments in them, and they are mostly pitched either in B-flat or E-flat, with some exceptions, one being the C-melody saxophone.
E flat
g flat, a flat, b flat, b, d flat, e flat, f, g flat
bros
b flat
A D flat is a C sharp... which is nothing
F, g, a, b flat, c, d, e, f