Sloan Digital Sky Survey
SkyServer DR15  
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SQL Tutorial
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 1. Introduction
 2. A Simple Query
 Practice
 3. Common Searches
 4. More Samples
 Practice
 5. Multiple Tables
 Practice
 6. Aggregate Fcns.
 7. Group By
 8. Order By
 Practice
 9. Views
 10. Functions
 Practice
 11. Conclusion
SQL Tutorial

More Practice Queries

Write queries to answer the astronomy questions in Practice 3 and 4. Use the Schema Browser when you need it.

Practice 3. What are the reddest galaxies in the area of sky near ra = 141?

Write a query to search for galaxies between ra = 140.9 and ra = 141.1 brighter than
g = 18.0 for which u - g > 2.2. Retrieve the Object ID, ra, dec, and the five final magnitudes.

Show Sample Solution

Practice 4. What are the highest-redshift quasars in the SDSS database?

Write a query to search for quasars for which we have obtained spectra (search the specObj table) with redshifts greater than 4.5 and good measurements (zWarning = 0). Retrieve each quasar's Photo ID, ra, dec, and redshift.

Show Sample Solution

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Enter your SQL query in the text box. The query is limited to 10 minutes and 100,000 rows.