percentageFROM SC21. query the average scores of different courses taught by different teachers from high to low.SELECT max (Z. T #) AS instructor ID, MAX (Z. tname) AS instructor name, C. C # AS course ID, MAX (C. cname) AS course name, AVG (Score) AS average ScoreFrom SC AS T, Course AS C, Teacher AS ZWhere T.C # = C. C # and C. T # = Z. T #Group by c. C #Order by avg (Score) DESC22. query the transcript of the following course scores of 3rd to 6th students: Enterprise Management (001), Marx
drive the signal only after the device that originally owns the signal releases control of the signal.S/t/sThe signal needs to be pulled up so that no device is driving him, keep an invalid level, that is, high level. The pull-up resistance is provided by the master control device. Tri-state logic and non-gate shows the three-state logic and non-gate. This circuit is actually composed of two and non-gates with a diode D2 . The right half of the dotted line is a non-portal with an active
UML,T4.score as database,Isnull (t1.score, 0) + isnull (t2.score, 0) + isnull (t3.score, 0) + isnull (t4.score, 0) as total scoreFrom student, SC left join SC as T1On SC. s # = t1.s # And t1.c # = '001'Left join SC as T2On SC. s # = t2.s # And t2.c # = '002'Left join SC as T3On SC. s # = t3.s # And t3.c # = '003'Left join SC as T4On SC. s # = t4.s # And
Bootstraptable+knockoutjs implementation of adding and deleting solutionsPreface: The previous article introduced the lower KO to change the package, did save a lot of JS code. Bo is a lazy person, always feel that the basis of the effects of adding and deleting the results can be directly generated by a tool, what the code is not written, it is more cool. So the study of the next T4 grammar, although not fully mastered, but it is a general understand
Not in and not exists, notinexists
Previously, I thought that not exists is the same as the previous parameter, but it was found after an experiment test. The selection method of Not exists and not in is very simple, that is, only select not exists because not in is added and will Not take the index. Not exists will go. This limits the use of not exists if necessary.Not exists indicates that the join query returns values other than the result of the join subquery,You can see the execution plan a
the inner layer as the query condition of the outer querySelect field List from table name where condition (select field List from table name where condition);Select name from Db3.user ORDER BY uid desc LIMIT 1;Select AVG (UID) from Db3.user;Select Name,uid from Db3.user where uidSelect name from Db4.t1;Select name from Db3.user where name in (select name from DB4.T1);Format 3 Connection QueryLeft JOIN query: The table on the left is the main display of query resultsSelect field List from table
when C # = ' 004 ' then score ELSE 0 END)/sum (Case C # when ' 004 ' then1 ELSE 0 END) as database average score, * SUM (case when C # = ' 004 ' and score >= 1 ELSE 0 END)/sum (caseWhen C # = ' 004 ' then 1 ELSE 0 END) as database percent passedFrom SC21, query different teachers teach different courses average from high to low displaySELECT Max (z.t#) as Teacher Id,max (Z.tname) as faculty name, c.c# as course ID,max (C.cname) As course name, AVG (score) as average scoreFrom SC as t,course as
(case when c # = '003 'THEN 1 ELSE 0 END) as uml pass percentage, SUM (case when c # = '004 'then score ELSE 0 END)/SUM (case c # WHEN '004 'then 1 ELSE 0 END) AS database average score, 100 * SUM (case when c # = '004 'AND score> = 60 THEN 1 ELSE 0 END) /SUM (case when c # = '004 'THEN 1 ELSE 0 END) AS database pass percentageFROM SC21. query the average scores of different courses taught by different teachers from high to low.SELECT max (Z. T #) AS instructor ID, MAX (Z. tname) AS instructor
from high to low.Copy codeThe Code is as follows:SELECT max (Z. T #) AS instructor ID, MAX (Z. tname) AS instructor name, C. C # AS course ID, MAX (C. cname) AS course name, AVG (Score) AS average ScoreFrom SC AS T, Course AS C, Teacher AS ZWhere T.C # = C. C # and C. T # = Z. T #Group by c. C #Order by avg (Score) DESC
22. query the transcript of the following course scores of 3rd to 6th students: Enterprise Management (001), Marx (002), UML (003), Database (004)[Student ID], [Student name], e
(case when c # = '003 'THEN 1 ELSE 0 END) as uml pass percentage, SUM (case when c # = '004 'then score ELSE 0 END)/SUM (case c # WHEN '004 'then 1 ELSE 0 END) AS database average score, 100 * SUM (case when c # = '004 'AND score> = 60 THEN 1 ELSE 0 END) /SUM (case when c # = '004 'THEN 1 ELSE 0 END) AS database pass percentageFROM SC21. query the average scores of different courses taught by different teachers from high to low.SELECT max (Z. T #) AS instructor ID, MAX (Z. tname) AS instructor
'Then 1 else 0 end) as UML pass percentage, Sum (case when C # = '004 'then score else 0 end)/sum (Case C # When '004 'then 1 else 0 end) as database average score, 100 * sum (case when C # = '004 'and score> = 60 then 1 else 0 end) /sum (case when C # = '004 'Then 1 else 0 end) as database pass percentageFrom SC21. query the average scores of different courses taught by different teachers from high to low.Select max (Z. T #) as instructor ID, max (Z. tname) as instructor name, C. C # As course
T, or the node value returned by the Find_node operation has not been looked up, that is, a closer node is not found.
5. Through the above search operation, x obtains the node information of K closest to T.
Note: The term "closest" is used here because a node with an ID value of t does not necessarily exist in the network, meaning that T is not assigned to any computer.
The process of finding peers-list is replaced by a find_value action, but note that the differences mentioned above can be des
();
}
Return MyObject
}
}
Creating a Thread class
Package COM.WEISHIYAO.LEARN.DAY8.SINGLETON.EP2;
public class Mythread extends Thread {
@Override public
void Run () {
System.out.println ( Myobject.getinstance (). Hashcode ());
}
To create a running class
Package COM.WEISHIYAO.LEARN.DAY8.SINGLETON.EP2;
public class Run {public
static void Main (string[] args) {
mythread t1 = new Mythread ();
T1.start ();
}
Run results
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good enhancement in data verification, you can directly use the System. componentModel. in DataAnnotations, special attributes such as RequiredAttribute and RangeAttribute are used to set verification rules, which is very convenient. In addition, this verification rule is still passed through the server and client, which largely satisfies the basic requirements for data verification. It would be better if the client can directly support the jquery verification library instead of using the Micro
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