Count(*) will count all records including nulls and count (column

Hi Guys,

I have been to L& T last week ..Please find the questions
mentioned below
1)Slowly changing dimension types
2)DML statement
3)DDL statement
4)write a syntax to create database
5) differences between count(*) and count(column)
6) differences between union and union all
7) what is decode
8) what is NVL
9) Arrange the values in ascending order 10,5,20,15,null
10)Primary and surrogate key
11)what is group by clause does?
12)what is difference between truncate and delete
13)what is difference between OLAP and OLTP ?
14)Architecture of Datawarehouse
15)how do you test the data validation from source as (flat
file and xml) to staging tables.
16)what is shedule and time bound

the mentioned above question asked in two rounds.all the
best

Question Posted / vignesh

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Answer Posted / vignesh

Count(*) will count all records including nulls and count
(column_name) will give count of non-null values only.

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