Answer / sivachandran

we can use 12 trigger in single table.

what are the advantages of sql ? : Sql dba

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Which join condition can be specified using on clause?

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What is the mutating table and constraining table?

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what are the different type of sql's statements ? : Sql dba

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How many types of literals are available in pl sql?

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Is trigger a stored procedure?

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What is blind sql injection?

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Where are my tempfiles, I don't see them in v$datafile or dba_data_file?

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How to add Foreign key in a table after the creation of the table?

5 Answers   Satyam,

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How many disk partitions should I have?

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how to check the 3rd max salary from an employee table? One of the queries used is as follows: select sal from emp a where 3=(select count(distinct(sal)) from emp b where a.sal<=b.sal). Here in the sub query "select count(distinct(sal)) from emp b where a.sal<=b.sal" or "select count(distinct(sal)) from emp b where a.sal=b.sal" should reveal the same number of rows is in't it? Can any one here please explain me how is this query working perfectly. However, there is another query to get the 3rd highest of salaries of employees that logic I can understand. Pls find the query below. "select min(salary) from emp where salary in(select distinct top 3 salary from emp order by salary desc)" Please explain me how "select sal from emp a where 3=(select count(distinct(sal)) from emp b where a.sal<=b.sal)" works source:http://www.allinterview.com/showanswers/33264.html. Thanks in advance Regards, Karthik.

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what are all the different normalizations? : Sql dba

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