SQL Tutorial: More Practice Queries
SQL Tutorial
SQL Tutorial
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 1. Introduction
 2. A Simple Query
 3. Common Searches
 4. More Samples
 5. Multiple Tables
 6. Aggregate Fcns.
 7. Group By
 8. Order By
 10. Functions
 11. Conclusion

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 = 195?

Write a query to search for galaxies between ra = 194.9 and ra = 195.1 brighter than
g = 18.0 for which u - g > 2.2. Retrieve the Object ID, ra, dec, and the five final magnitudes.

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 high confidence measurements (zconf > .35). Be sure to retrieve both quasars and the objects classified as high-redshift quasars. Retrieve each quasar's Photo ID, ra, dec, and redshift.

How many results do you get?



Enter your SQL query in the text box. The query is limited to 90 seconds and 100,000 rows.