SQL exercises
SQL exercises
Language Русский English select

January 14, 04:54 MSK
form


SQL Exercises is intended for acquiring good practical experience,
which is focused on data operation, namely on SQL DML. Certain exercises for beginners are provided on the site,
they are supplied with the necessary reference source on SQL syntax with a great number of examples.
Apart from them, 3 rating stages are suggested, they are aimed at testing of specialists and their certification.
The source is absolutely free of charge, and the certificate purchase has a voluntary basis.
NOTE: Your browser should support Cookies and Javascript to provide correct usage of this site. If you use content filter,
it should allow opening child windows to explore help pages.
Login:
Password:
forgot password?
Registration
Ratings
#8226; A class="menu" href="/rating.php" Top 100A
#8226; A class="menu" href="/rating_cyr.php" "Liberal" ratingA
#8226; A class="menu" href="/rating_formula.php" Olympic ratingA
#8226; A class="menu" href="/learn_rating.php" TOP 100 of Learning StageA
#8226; A class="menu" href="/rating_sum.php" Rating by summation of ranksA
#8226; A class="menu" href="/users_page.php"Top 10 (photos)A
#8226; A class="menu" href="/week_rating.php"Last-week resultsA
#8226; A class="menu" href="/quest_rating.php"Rating of second-stage exercises nbsp(average)A
#8226; A class="menu" href="/quest_rating_median.php"Rating of second-stage exercises nbsp(median)A
#8226; A class="menu" href="/author_rating.php"Author's ratingAform name="fm1" action="/rating_2st.php" method="post" onSubmit="this.subm3.disabled=true;" #8226; font class="menuwa"2nd stage rating up to exercise:br enter No fontinput type="text" id="nn" name="nn" class="menuwa" size="2" maxlength="3"
value="64"input type="submit" name="subm3" style="width: 90px; font-size:9px;" value="and click here"formform name="fm2" action="/rating_3rd.php" method="post" onSubmit="this.subm4.disabled=true;" #8226; font class="menuwa"Rating on the exercise:br enter Nofontinput type="text" id="nn4" name="nn4" class="menuwa" size="2" maxlength="3"
value="31"input type="submit" name="subm4" style="width: 90px; font-size:9px;" value="and click here"formform name="fm3" action="/rating_4th.php" method="post" onSubmit="this.subm5.disabled=true;" #8226; font class="menuwa"Optimistic ratingbr enter factorfontinput type="text" id="nn5" name="nn5" class="menuwa" size="2" maxlength="3" value="3"input type="submit" name="subm5" style="width: 90px; font-size:9px;" value="and click here"form
Statistics
#8226; A class="menu" href="/rating_day.php" Today statisticsA
#8226; A class="menu" href="/rating_1st.php" Site's old residentsA
#8226; A class="menu" href="/leaders.php"Recent leaders activityA
#8226; A class="menu" href="/leaders_ex.php"Сhanges in exercises' TOP 10A
#8226; A class="menu" href="/chart.php"Results' chartA
SQL exercises
#8226; A class="menu" href="/learn_exercises.php" SELECT (learning stage)A
#8226; A class="menu" href="/exercises.php" SELECT (rating stages)A
#8226; A class="menu" href="/dmlexercises.php" DML A
Forums
#8226; A class="menu" href="/forum/Lforum.php" Learning stageA
#8226; A class="menu" href="/forum/forum.php" Rating stagesA
#8226; A class="menu" href="/favorites/" FavoritesA
#8226; A class="menu" href="/forum/search/"SearchA
Certification
#8226; A class="menu" href="/certification/certification.php" About certificationA
#8226; A class="menu" href="/users_page.php?cs=4"Certified professionalsA
#8226; A class="menu" href="/certificate_statistics.php"StatisticsA
#8226; A class="menu" href="/certification/certification.php"Confirm certificateA
HELP
#8226; SQL(DML) help
#8226; FAQ
#8226; Send message
#8226; Books Articles
Query optimization
#8226; Query plan
#8226; Rating by cost
#8226; Optimization competition rules
Transact-SQL tests
Modelling of data
Personalpage
Exercises voting
Developers Thanks
For employers
References
Feedback
Support SQL-EX.RU
Poll
For what DBMS, besides SQL Server, you would like to have exercises on the site?
Oracle
PostgreSQL
MySQL
Another
Nothing is necessary any more
View Results
Site news 2010-12-06All the news Week news
Certified within this week:
Malyshok A.A. (Magnetic)
Confirm certificate
Competition on optimization of queries will be launched in nearest future. Query optimization competition rules.
Searching and bookmarks service have appeared in the site forum.
There are exercises on SELECT statement (presently 74 exercises on learn stage and 171 exercises on rating stages) and on other
data manipulation operators - INSERT, UPDATE, DELETE (23 exercises).
The rating of members is carried on SELECT exercises. See test conditions.
The book "SQL. Problems and solutions" , which is analyzing the characteristic mistakes admitted at the solution of the first stage exercises on the site, was originally published in Peter Publishing Company.
Newsletters of our site (in Russian) on Subscribe.Ru:
FONT
Read last news letter
Today we have 54 visitors (7 new).
18 exercises solved (7 on SELECT and 11 on DML),
on learning stage - 82
Practical skills of SQL language
This site will help everyone to gain or improve skills in building
SQL Data Manipulation Language statements. To train You will have to build yourself
the SQL statements for retrieval or modification of specific data required in the exercises.
When Your query is incorrect, You will be able to see rows returned by the correct
query along with that returned by Your query. Furthermore, you may execute arbitrary
DML statements on available databases by setting the "Without checking" option. There are
four levels of difficulty (from 1 to 4), You may see it in second column of
exercises list. We propose the exercises on retrieving data (SELECT statement) and
the exercises on modifying data (INSERT, UPDATE, and DELETE statements). Your success in the solving the exercises are shown by a rating of participants.
As this takes place, there are three stages:
the first one (first 30 exercises) is performed without time control for an individual
exercise, the second one (begins with the exercise #31) controls time for completion of each
task. At the third stage which refers to optimizing and begins with exercise #139, it is required not only to solve an exercise correctly, but also time of execution of inquiry should be commensurable with time of execution of the author's solution.
Exercises of the first stage are available without registration and may be solved
in any order You like. The solution of the rest of exercises requires registration.
REGISTRATION IS FREE as this for all other services of the site. In the third column of exercises list You
will be able to see ("OK") notes with the numbers of done exercises, but that
is available only to the registered users. In fact, that is the main reason for registration.
If You would like to visit our web site again, You won't have to recollect which
exercises You have done already and which You haven't. If You don't want to register,
You may enter as a guest, but in that case Your results won't
be traced by the system. Registered users also may discuss the solutions to exercises in our forum.
NOTE: The query stated incorrectly may return the "correct" data on a current state of database.
For this reason You should not be surprised if the results of incorrect query are
coincide with the results of right one with Your query is estimated as incorrect by the Verifying system.
NOTE: Your browser should support Cookies and Javascript to provide correct usage of this site. If you use content filter, it should allow opening child windows to explore help pages.
Certification
Successful testing of yours can be confirmed by the certificate "SQL Data Manipulation Language Specialist".
We support quality of our certificate by periodically replacing exercises and changing
the certificate requirements. More about certification. What does the certificate give to you?
P
SQL syntax used
User's queries are executed by SQL server that brings some limitations to the
syntax of SQL statements. We use Microsoft SQL Server 2005 now. That is why You should follow
the syntax of this realization when building queries. It should be noted that SQL syntax,
implemented in Microsoft SQL Server, is close to that of SQL-92 standard. But there are some
distinctions, among them is absence of NATURAL JOIN of tables. Supplied help on SQL Data Manipulation Language is held in accordance
with SQL-92 standard and contains information necessary for solving the exercises. In the same place it is possible to find features of used realization (SQL Server 2005).
Top 10 resultsPerson
ScoresDaysDays_2
Days_3Scores_3
Kreslavskij O.M. (Arcan)
4131436153.480
108.882 96
Karasyova N.V. (vlksm)
4131702157.141
126.353 96
Dubinskij A.V. (_yizraor)
407415263.948
339.657 90
Derzhal'tsev V.A. (MadVet)
3962077150.294
107.547 87
Sal'nikov S.A. ($erges)
39210508.511
7.886 83
Zotov P.G. (Ozzy)
3901025214.179
190.297 80
Drozdkov A.N. (anddros)
39095210.065
9.299 73
Bojko D.M. (Angellore)
39012451135.371
246.257 73
Bezhaev A.Yu. (Baser)
38825293.104
68.966 73
Tarasov D.B. (Gavrila)
381196499.480
57.053 69
Top 100 | Candidates
Last-week results
Rating of second-stage exercises nbsp(average)

Site news
Week news
Certification
#8226; About certification
#8226; Certified professionals
#8226; Statistics
SQL exercises
#8226; SELECT (learning stage)
#8226; SELECT (rating stages)
#8226; DML
#8226; Modelling of data
Forums
#8226; Learning stage
#8226; Rating stages
#8226; Favorites
#8226; Search
Ratings
#8226; Top 100
#8226; Today statistics
#8226; Recent leaders activity
#8226; Rating of second-stage exercises nbsp(average)
HELP
#8226; SQL(DML) help
#8226; FAQ
#8226; Send message
#8226; Books Articles
Performance
#8226; Query plan
#8226; Rating by cost
Profile
References
Copyright SQL-EX copy; 2002-2010. All rights reserved.
contact
DIV
HTML