  In the course of the Sloan Digital Sky Survey (SDSS-I), a large fraction of
the surveyed area was observed more than once due to field tiling overlap,
usually at different epochs. We utilize some of these data to perform a
supernova (SN) survey at a mean redshift of z=0.2. Our archival search, in ~ 5%
of the SDSS-I overlap area, produces 29 SN candidates clearly associated with
host galaxies. Using the Bayesian photometric classification algorithm of
Poznanski et al., and correcting for classification bias, we find 17 of the 29
candidates are likely Type Ia SNe. Accounting for the detection efficiency of
the survey and for host extinction, this implies a Type Ia SN rate of
R=14.0+(2.5,1.4}-(2.5,1.1}+/-2.5 10^-14 h(70)^2 yr^-1 L_sun^-1, where the
errors are Poisson error, systematic detection efficiency error, and systematic
classification error, respectively. The volumetric rate is
R=1.89+(0.42,0.18)-(0.34,0.15)+/-0.42 10^-5 yr^-1 h(70)^3 Mpc^-3. Our
measurement is consistent with other rate measurements at low redshift. An
order of magnitude increase in the number of SNe is possible by analyzing the
full SDSS-I database.
