SQL Interview Questions_part 1

Only for study and record, I will keep trying all tests that relate to my carrier.

I heard many companies using TESDOME for Coding Test for the job application and they gave many practice problems for various languages. Of course, I will try to solve all questions about SQL, but also Python too. (I know  HackerRank problems are waiting for me.. haha..)

 

I will upload 3 problems in one post. One of my friends told me it is hard to read... 

 

Let's begin. 

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SQL Interview Questions

1. Students

[Problem]

Given the following data definition, write a query that returns the number of students whose first name is John. String comparisons should be case sensitive.

 

[My Answer]

select count(*) from students
where firstName ='John'

update enrollments set year = 2015
where id >= 20 and id <= 100;

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3. Pets

[Problem]

Information about pets is kept in two separate tables:

Write a query that select all distinct pet names.

 

[My Answer]

select name from cats
union
select name from dogs

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