PostgreSQL: using a calculated column in the same query

by

You need to wrap the SELECT statement into a derived table in order to be able to access the column alias:

select cost1,
       quantity_1,
       cost_2,
       quantity_2
       total_1 + total_2 as total_3
from (
    select cost_1, 
           quantity_1, 
           cost_2, 
           quantity_2, 
           (cost_1 * quantity_1) as total_1,
           (cost_2 * quantity_2) as total_2
    from data
) t

There won’t be any performance penalty on that.

(I’m really surprised that your original SQL statement runs at all in a DBMS)

More Related Contents:

  1. Using an Alias column in the where clause in Postgresql
  2. Why can’t I use column aliases in the next SELECT expression?
  3. Select first row in each GROUP BY group?
  4. How to concatenate strings of a string field in a PostgreSQL ‘group by’ query?
  5. How to use RETURNING with ON CONFLICT in PostgreSQL?
  6. PostgreSQL DISTINCT ON with different ORDER BY
  7. IN vs ANY operator in PostgreSQL
  8. Query with LEFT JOIN not returning rows for count of 0
  9. How do I force Postgres to use a particular index?
  10. How to create a temporary function in PostgreSQL?
  11. Polymorphism in SQL database tables?
  12. Record returned from function has columns concatenated
  13. Query for element of array in JSON column
  14. INSERT rows into multiple tables in a single query, selecting from an involved table
  15. Casting NULL type when updating multiple rows
  16. How to round an average to 2 decimal places in PostgreSQL?
  17. Best way to delete millions of rows by ID
  18. Explain JOIN vs. LEFT JOIN and WHERE condition performance suggestion in more detail
  19. How to find a table having a specific column in postgresql
  20. How to read the contents of an .sql file into an R script to run a query?
  21. PostgreSQL JOIN with array type with array elements order, how to implement?
  22. Trim trailing spaces with PostgreSQL
  23. INSERT COMMAND :: ERROR: column “value” does not exist
  24. Return multiple columns and rows from a function PostgreSQL instead of record
  25. Check whether string is a date Postgresql
  26. SQL LIKE condition to check for integer?
  27. Counting the number of occurrences of a substring within a string in PostgreSQL
  28. How to use SQL LIKE condition with multiple values in PostgreSQL?
  29. Why isn’t row level security enabled for Postgres views?
  30. Is there a postgres CLOSEST operator?

Leave a Comment