on sql basic question [closed]

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Q. display all the salaries and display total sal at the end? Q. how many column are inserted in a single table?

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Q1:

SQL> select sum(sal)
  2    from emp
  3   group by rollup(empno)
  4  /

  SUM(SAL)
----------
       800
      1100
      1300
      1500
      1600
      3000
      3000
      5000
       950
      1250
      1250
      2450
      2850
      2975
     29025

15 rows selected.

Q2: Please explain this question some more.

Regards, Rob.

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1. select sal from empsal union select SUM(sal) from empsal

2. I think you want to get the count of columns for a table. You can do that be following query:

   select count(*) from information_schema.columns where table_name = ''

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Solution 1: Use Roll Up Function for first question

select empno,sum(sal) from emp group by rollup((sal,empno));

Solution 2: Use Grouping Sets

select empno,sum(sal) from emp group by GROUPING SETS ((empno),())