Practice Using Joins
Write queries to answer the astronomy questions in Practice 5 and 6.
Use the Schema
Browser when you need it. (Note: these queries will probably take the full
90 seconds to execute... just let them run until you see the results.)
Practice 5. How can you look up image data, plates and spectra
of moderately bright nearby galaxies?
Write a query to find
galaxies for which we have spectra that have g magnitude between 17 and 17.4 and
redshift less than 0.05.
For each galaxy, retrieve the object ID, the five magnitudes (u,g,r,i,z), the redshift,
the plate/MJD number, and the fiber number.
Practice 6. What types (templates) of
quasars have high redshifts?
Write a query to find the
template number matched to all high redshift quasars (redshift
greater than 2.5).
HINT: template number is in the Cross-Correlation Redshifts table.
Retrieve the objects' ra, dec, u, g, r, i, z, redshift, and tempno.