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AlejandroR
Asked: 2022-08-02 03:32:36 +0800 CST 2022-08-02 03:32:36 +0800 CST

sum and mean of two columns in postgres

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Good morning, I have a database in which I store students and notes. I have the notes of the first exam and the second exam and I have a third empty column in which I want to store these notes.

I'm trying with select to simulate it but it doesn't get me the average of the sum of the two columns:

select nombre, avg(primerexamen+segundoexamen) as media  from dl.modulo1 group by nombre;

If someone can lend me a hand to get this operation.

I plan to do an insert later with the operation indicating that it has to save it in the quarternote column

postgresql

1 Answers

  1. Best Answer

    To calculate this mean, you would have to first calculate one and then the other:

    select nombre, avg(primerexamen), abg(segundoexamen)  from dl.modulo1 group by nombre;

    But this is going to return it to you in two columns, so you could do a simple equation to calculate the mean:

    select nombre, (avg(primerexamen) + abg(segundoexamen)) / 2 as Media from dl.modulo1 group by nombre;

    This way it should work fine for you.

    I wait your answer.

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