Sql developer Interview Questions

SQL stands for Structured Query Language, and SQL developers create SQL databases and the applications that work with them. They often use design tables and storing procedures for stability, reliability and performance. In an SQL developer interview, employers often ask questions about your programming knowledge and problem-solving skills.

996 Sql Developer interview questions shared by candidates

Top SQL Developer Interview Questions & How to Answer

Here are three top SQL developer interview questions and tips on how to answer them:

Question No. 1: What are the types of keys in SQL and when would you use them?

How to answer: This question lets you demonstrate your knowledge of SQL. Discuss the most common types of SQL keys and talk about how they can identify rows and columns in tables. Keys work as unique identifiers, allowing users to retrieve data easily.

Question No. 2: What are the types of normalisation available in SQL and how do you use them?

How to answer: People use SQL normalisation to organise data and reduce redundancies. You can demonstrate your experience by discussing the normalisation methods you use the most. For example, many developers divide a large table into several smaller ones for easier readability.

Question No. 3: Which programming languages are you familiar with?

How to answer: Many SQL developers also use JavaScript, HTML, Python, PL/SQL and other languages. Mention the languages you know and how you used them at your previous job. Also, tell the interviewer about any programming certifications you received.

Top Interview Questions

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Shriram Value Services
Software Engineer(SQL) was asked...17 March 2017

SQL - Trigger, Stored Procedure, SQL Basics, truncate & delete HR - Joins, Multirow functions

4 Answers

Trigger is a kind of special stored procedure which will execute automatically when a when an event occures in database server. Less

Stored procedure is a prepared SQL code which is saved for reusing.

Truncate is similar to the delete command but it removes entire table. Delete is the command Which is used to remove some data by using where clause. Less

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Berkshire Hathaway

If I knew what the cross apply operator was

4 Answers

If they want the word its join, a description could be "the Cartesian product of multiplying the tables" and an example would be "like merging two matrices except every column may be of incongruent variables creating a result with polynomial rows, (which is likely no longer normalized to the form level of the database)" Less

An Apply operator is a join type that the query engine evaluates in sequential order because the right-hand table object can reference data in the left-hand table object. The Cross Apply operator is the Apply operator that acts like an Inner Join, eliminating any records in the left-hand table object that have a null match in the right-hand table object. Less

An Apply operator is a join type that the DB engine evaluates in sequential order because the right-hand table object can reference data in the left-hand table object. The Cross Apply operator is the Apply operator that acts like an Inner Join, eliminating any records in the left-hand table object that have a null match in the right-hand table object. Less

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ISN Software

Given 2 dates, return a result set that outputs a number for each week between the two. (They will ask the numbered week to be the sequential week and also the calendar week. Prepare for given start date to be start mid-week.)

3 Answers

--Given 2 dates, return a result set that outputs a number for each week between the two. (They will ask the numbered week to be the sequential week and also the calendar week. Prepare for given start date to be start mid-week.) declare @temp date, @d date = '2020-01-01', @dd date = '2020-03-01', @i int = 0 declare @t table (w int, d date); declare @w int, @wp int = 0 set @temp = @d; while @temp @wp begin insert into @t values (@w, @temp) set @wp = @w end end select * from @t; Less

--Given 2 dates, return a result set that outputs a number for each week between the two. (They will ask the numbered week to be the sequential week and also the calendar week. Prepare for given start date to be start mid-week.) declare @temp date, @d date = '2020-01-01', @dd date = '2020-03-01', @i int = 0 declare @t table (w int, d date); declare @w int, @wp int = 0 set @temp = @d; while @temp @wp begin insert into @t values (@w, @temp) set @wp = @w end end select * from @t; Less

DECLARE @Start_Dt DATE = '2020-01-07', @End_Dt DATE = GETDATE(), @SequencialWeek_No INT = 1, @OldWeek_No INT = 0, @Week_No INT = 0; DROP TABLE IF EXISTS #Temp; CREATE TABLE #Temp ( Date DATE, Week_No INT, SequencialWeek_No INT ); WHILE @Start_Dt <= @End_Dt BEGIN SET @OldWeek_No = @Week_No; SET @Week_No = DATEPART(wk, @Start_Dt); SET @SequencialWeek_No = CASE WHEN @Start_Dt = '2020-01-07' THEN 1 WHEN @OldWeek_No = @Week_No THEN @SequencialWeek_No ELSE @SequencialWeek_No + 1 END; INSERT INTO #Temp ( Date, Week_No, SequencialWeek_No ) SELECT @Start_Dt, @Week_No, @SequencialWeek_No; SET @Start_Dt = DATEADD(DAY, 1, @Start_Dt); END; SELECT * FROM #Temp ORDER BY Date; Less

PwC

What is the result if we do following Null + 90

3 Answers

Always remember null + anything will be null. Also applicable for - ,* ,/

Null

Null .anything+ null is null

Home Credit International

Not unexpectedly, the manager was particularly interested in my experience in gathering requirements and creating designs.

3 Answers

What kind of design excersice did you have to present? something related to data modelling? I'm just curious Less

It was a high-level design for a loan application, including the architecture and data model for the application. Less

Because I had 12 years as team lead on a top priority application, I had good stories to relate about my experience gathering requirements and creating designs. Less

Page Industries

1. Aptitude, reasoning, English, C, C++ 2. Project 3. WAP for bubble sort. 4. WAQ for having clause 5. Multiple inheritance 6. OOPs concept

2 Answers

I answered well.

I want to know about is their any fixed criteria in apptitude?

Greenway Health

What's the difference between TRUNCATE and DELETE

2 Answers

Both delete the data but Delete is a DML command can roll back but Truncate is a DDL command and don’t roll back and faster than DML Less

one gets logged, the other doesn't so you have your performance hit. Need elevated permissions i.e. dbo for TRUNCATE Less

Oracle

how to transform a string into comma separated values

2 Answers

use split()

Listtag(string,delimeter)

Yardi Systems

Delete duplicate records from a table

2 Answers

Do they ask to write a program or only sql queries?

referr google

PwC

How to retrieve unique rows from database without using Distinct or Unique keyword

2 Answers

One of the method is select a ROWID among duplicate columns

One method is to use GROUP BY the column(s) you want as distinct.

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