ETL Testing : SQL queries based Interview questions and answers - 1

[@ShivShwetaVlogs]

Thanks for discussing these questions... 😊😊 Very much helpful for interviews

[@bhargavakotakonda6233]

Thank you so much sir,
For helping us

[@aditideshmukh1174]

Sir, min Or max is not to be used in question where we need to find min salary. We can use select * from (select row_number() over (partition by name order by salary asc) as the_val from table) as N where N.the_val = 1

[@etlqalabs5048]

Concept looks ok but SQL statement may not work if in Oracle .

[@komalishware2481]

Thank you

[@chandanmohanty8186]

Sir, I have 1 doubt at the play run time 36:59 where during odd retrieval we are getting emp no 10, 12 and 14 also. But they are even not odd. Am i miss understood something? Can u please help me

[@etlqalabs5048]

Odd or even here meaning row number as even or odd , it has nothing to do with empno being odd or even. So let say we have 4 rows in a table when I need to get odd rows in that case row number 1 and 3 will be displayed. Hope this clarifies

[@chandanmohanty8186]

@@etlqalabs5048 Thank you sir

[@ShivShwetaVlogs]

Hi Sir, please add this question in your next upcoming video,, SQL Query Top 1 selling product from last 10 days

[@etlqalabs5048]

Probably you would like to share more details on the table structure and exact query

[@sireeshareddy-n9r]

Thanks for this video. I have one question
If we have more than 5 lakh records how can we check data loaded from src to tar ??

[@etlqalabs5048]

Generally there could be 2 scenarios
1. Homogeneous system means source and target both are on the same database - you can use minus/except queries
2. Heterogeneous system where source and target are different - you have right some sort of scripting/code to compare the data from both

[@Dr.SyedSaifAbbasNaqvi]

​@@etlqalabs5048Sir, Can you cover heterogeneous sources where the src and target are from different databases using the scripting you mentioned.

[@sireeshareddy8046]

Thanks Sir .. I know using except we can check difference between source and target but they are asking it’s more records means query will take time that time how will u check ??

[@ashokrajann9351]

Set operators can be used between 2 tables only right??

[@etlqalabs5048]

I think , yes only 2 tables at a time until you use brackets to consolidate the output and use that as a input

[@aditideshmukh1174]

We can use 2 or more tables for set operators. 2 is in min requirement.

[@deveshpadgelwar8895]

Table A (Student ID, Student Name, Student Age)
table B (Student ID, Student Class, Student Section)
Select Student Name, Student Class, Student Section where Student Age between 16 to 18 and Student Section is 'D' How to find out sir ?

[@etlqalabs5048]

Just use inner join on studentid in both the tables , you already wrote the query, just add this extract condition in where clause . That's all

[@deveshpadgelwar8895]

@@etlqalabs5048 little confused sir?

[@jjjjy126]

Select a.studentName, b.studentClass, b.studentSection
from TableA a, TableB b
where a.studentId = b.studentId
And a.studentAge between 16 and 18
And b.studentSection = ‘D’;

[@jjjjy126]

Or,
Select a.studentName, b.studentClass, b.studentSection
from TableA a, TableB b
Inner join a.studentId on b.studentId where a.studentAge between 16 and 18
And b.studentSection = ‘D’;