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.)
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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.
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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. |
Answers
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