21 interview questions for developers (2026)

Easy

3 votes203 runs0 comment

What type of join returns all rows in the left-hand table, even if they have no match in the right-hand table?

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Koala rareat Feb 11, 2025

Easy

2 votes190 runs0 comment

How to rename a column in an existing table in Oracle?

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Koala rareat Feb 11, 2025

Easy

1 vote181 runs0 comment

What is the result of this Oracle query?

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NVL

Koala rareat Feb 11, 2025

Hard

1 vote174 runs0 comment

Which Oracle tool can be used to analyze SQL query performance?

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sql

Koala rareat Feb 11, 2025

Expert

1 vote169 runs0 comment

What does the following SQL query return?

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database

sql

Koala rareat Feb 11, 2025

Hard

1 vote168 runs0 comment

Where does Oracle log system errors and critical events ?

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logging

troubleshooting

Koala rareat Feb 11, 2025

Hard

1 vote162 runs0 comment

What type of index is recommended for columns with few distinct values in Oracle?

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indexes

bitmap

Koala rareat Feb 11, 2025

Medium

0 vote180 runs0 comment

What happens after executing this code in Oracle?

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transactions

rollback

Koala rareat Feb 11, 2025

Easy

0 vote174 runs0 comment

What is the main function of the `DBMS_SCHEDULER` package in Oracle?

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database

scheduling

Koala rareat Feb 11, 2025

Easy

0 vote163 runs0 comment

What does this PL/SQL code do?

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cursors

loops

Koala rareat Feb 11, 2025

Medium

0 vote161 runs0 comment

What are the primary uses of a Materialized View in Oracle?

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Koala rareat Feb 11, 2025

Medium

0 vote159 runs0 comment

What does the "INSERT /+ APPEND /" instruction do in Oracle?

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sql

insert

direct path

Koala rareat Feb 11, 2025

Medium

0 vote156 runs0 comment

What is the role of the SYSTEM tablespace in Oracle?

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database

tablespace

Koala rareat Feb 11, 2025

Easy

0 vote153 runs0 comment

How to grant SELECT rights on a table in Oracle?

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Koala rareat Feb 11, 2025

Hard

0 vote152 runs0 comment

What is the length of the string "\u00e9" in Oracle?

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Koala rareat Feb 12, 2025

Medium

0 vote151 runs0 comment

Which Oracle architecture component contains the in-memory data cache?

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SGA

Koala rareat Feb 11, 2025

Medium

0 vote151 runs0 comment

How to backup a database with RMAN in Oracle?

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backup

RMAN

Koala rareat Feb 11, 2025

Easy

0 vote150 runs0 comment

What's the difference between VARCHAR2 and CHAR in Oracle?

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varchar2

char

Koala rareat Feb 11, 2025

Easy

0 vote134 runs0 comment

What happens after executing this code in Oracle?

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transactions

rollback

Koala rareat Feb 11, 2025

Medium

0 vote124 runs0 comment

How to remove all data from an Oracle table without logging the transaction history?

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sql

truncate

Koala rareat Apr 22, 2025

21 interview questionsfor developers (2026)

Test your developer skills before an interview with 21 corrected questions on 80+ topics. Beginner, Intermediate or Expert level.

What type of join returns all rows in the left-hand table, even if they have no match in the right-hand table?

How to rename a column in an existing table in Oracle?

What is the result of this Oracle query?

Which Oracle tool can be used to analyze SQL query performance?

What does the following SQL query return?

Where does Oracle log system errors and critical events ?

What type of index is recommended for columns with few distinct values in Oracle?

What happens after executing this code in Oracle?

What is the main function of the `DBMS_SCHEDULER` package in Oracle?

What does this PL/SQL code do?

What are the primary uses of a Materialized View in Oracle?

What does the "INSERT /+ APPEND /" instruction do in Oracle?

What is the role of the SYSTEM tablespace in Oracle?

How to grant SELECT rights on a table in Oracle?

What is the length of the string "\u00e9" in Oracle?

Which Oracle architecture component contains the in-memory data cache?

How to backup a database with RMAN in Oracle?

What's the difference between VARCHAR2 and CHAR in Oracle?

What happens after executing this code in Oracle?

How to remove all data from an Oracle table without logging the transaction history?

21 interview questionsfor developers (2026)

Test your developer skills before an interview with 21 corrected questions on 80+ topics. Beginner, Intermediate or Expert level.

What type of join returns all rows in the left-hand table, even if they have no match in the right-hand table?

How to rename a column in an existing table in Oracle?

What is the result of this Oracle query?

Which Oracle tool can be used to analyze SQL query performance?

What does the following SQL query return?

Where does Oracle log system errors and critical events ?

What type of index is recommended for columns with few distinct values in Oracle?

What happens after executing this code in Oracle?

What is the main function of the `DBMS_SCHEDULER` package in Oracle?

What does this PL/SQL code do?

What are the primary uses of a Materialized View in Oracle?

What does the "INSERT /*+ APPEND */" instruction do in Oracle?

What is the role of the SYSTEM tablespace in Oracle?

How to grant SELECT rights on a table in Oracle?

What is the length of the string "\u00e9" in Oracle?

Which Oracle architecture component contains the in-memory data cache?

How to backup a database with RMAN in Oracle?

What's the difference between VARCHAR2 and CHAR in Oracle?

What happens after executing this code in Oracle?

How to remove all data from an Oracle table without logging the transaction history?

What does the "INSERT /+ APPEND /" instruction do in Oracle?