SQL certification

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Our SQL test will help you understand your proficiency with the Structured Query Language (MariaDB dialect). This test covers the following topics: Creating and Populating Databases, Basic Queries, Filtering, Querying Multiple Tables, Sets, Data Conversion and Manipulation, Grouping and Aggregates, Subqueries, Joins, Conditional Logic, Transactions, Indexes and Constraints, Views, Metadata. Difficulty level: for experienced developers.

Number of questions: 100
Time limit for question: 60 seconds

Assuming `tbl.visible` field can have only values of `0` or `1`, what will the following query produce? UPDATE tbl SET visible = ( SELECT !visible as visible FROM tbl WHERE id = 2 ) WHERE id = 2

Choose one:
  • Value of visible will become 1
  • Value of visible will be inverted
  • Value of visible will become 2
  • The query contains an error
  • The query will be ignored

How many bytes will take the a varchar(2) field after it's been assigned the "abcd" value?

Choose one:
  • "2"
  • "3"
  • "4"
  • "5"

If the length of the result returned by a string functions is longer than a certain value, the function will return NULL. What is this maximum length?

Choose one:
  • 256
  • max_allowed_packet
  • _max_varchar
  • 65535
  • There are no such limits

Our certificates

Getting your career started and need to impress a potential employer? We can conduct any of our tests in a manner that will allow us to verify your identity and check that the test result is indeed your own work. If you pass the test, we will issue a certificate just like the one pictured. You will be then able to obtain both an electronic certificate suitable for sharing on Facebook and Linkedin, a corresponding badge on your personal page, and a downloadable PDF version for printing.

Certificate authencity can be verified with a special tool. Simply enter the certificate ID to verify claims of completion.

PDF version:
Online competence badge:
Certified in SQL
2017-11-18 #xxxx-xxx-xxx-xxx

Price: $5

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