.... Cool
And then follow the same line of thought to some of the other common SQL has been optimized, the effect immediately effective
After 30 minutes to check the slow SQL records file, not good, found that a good SQL became gray often slow, God horse situation?
After analyzing and testing the reason for adding a federated index, and having an or in the SQL statement, the problem is excluded when this or union is used.
This time to come to a l
(+)----results equivalent to outer joinsUse of data dictionariesSelf-connect (cheat yourself): select * from Z_course C1, Z_course C2 where C1.cour_code=c2.p_cour_codeHierarchical queryConnect by PRIOR Connection condition start with start condition SELECT * FROM Z_course t connect by prior T.cour_code=t.p_cour_code start with t.cour_name like '% International 'Pseudo-column:Level: plus a column of display levels Select t.*, level from Z_course t connect by prior T.cour_
151510 1450 Select Se.last_name,se.salary,se.dept_id,temp.avgsalFrom S_emp SE, (Select Dept_id,avg (Salary) AvgsalFrom S_empGROUP BY dept_id) Tempwhere se.dept_id = temp.dept_idand Se.salary > temp.avgsal; 1. Query for employee information2. For example, to find out the staff information in Sector 41st, which is higher than the average salary of department 41st (this department) Select AVG (Salary), dept_idFrom S_empGroup BY DEPT_ID; Select last_name,salary,dept_idFrom S_emp; Select S1.last_na
join ... On and Traditional Association query queries, the SID appears two times. 4.LEFT OUTER JOIN ... On "SELECT * from students left OUTER JOIN transcript USING (SID) where transcript.date=2015-6"; Select the table students all the data and add the transcript data to the students table, and if the transcript does not meet the criteria, it is not added to the result table, and NULL indicates 5.RIGHT OUTER JOIN ... On "SELECT * from students right OUTER JOIN transcript USING (SID) where transc
Tags: problem SP c new SQL table BS r ROMIn a subquery, if you want to implement the following functions:Select Lib,count (*), select SUM (NEWSNO) from Table1 GROUP by LibFrom Tabel1 t1,table2 T2 where T1.newsno =t2.newsnoGroup by LibYou will be prompted that the subquery returns more than one value. "Error, meaning that a subquery cannot return multiple results, only one result can be returned.Therefore, you can use the following method instead:Select Lib,count (*), select SUM (newsno) from Tab
Briefly in the previous article about the ES synchronization data script roughly, but the actual situation is certainly not as simple as the script in the previous article. For example, I now have three tables, two entity tables, and an association table. The approximate implementation is as follows:The bin directory establishes a Statefile.json file:{ ' type ': ' JDBC ', "Statefile": "Statefile.json", "JDBC": { "url": "jdbc:mysql://", "User": "", "Password": "",
, you cannot use the prefix index for both ORDER by and GROUP by, and you cannot use the prefix index for overwrite scans. # 语法
ALTER TABLE table_name ADD KEY(column_name(prefix_length)); # 示例 ALTER TABLE city ADD KEY(cityname(7))
1
2
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Overwrite IndexA bit similar to the federated Index, which is to fetch the data only by reading the index when querying T, without having to query the related table two times. The leaf no
INNER JOIN: (INNER join)Inner joins use comparison operators to match rows in two tables based on values in the universal columns of each table(1) SELECT ... From table 1INNER JOIN table 2ON ...SELECT S.sname,c.courseid,c.scoreFrom score as CINNER JOIN Students as SOn c.studentid = S.scode(2) SELECT ... From table 1, table 2WHERE ...SELECT Students.sname, Score.courseid, Score.scoreFrom Students,scoreWHERE Students.scode = Score.studentidOuter joins:(1) LEFT OUTER join: The data of the left tabl
Label:Group:SELECT * FROM (SELECT row_number () over (ORDER by ProjId) as row_number,* from (Select Projapplydate,projproperty,projid,projstatuscurrent,projguid,projetpid,projregionid,projname,projaddress , Projareasize,projcost,projcreatetime,projchargeperson,projchargepersonphone,projapplyetp,projapplyperson, Projapplypersonphone,projconstructetp,projconstructpm,projconstructpmphone,projdirector,projdirectorphone, Projsafeorgz,projcode,projisenable, Min (consigndate) as Consigndate,max (conbal
1. Simple manual correlationFirst, the results are queried and put into a variable, and then queryu = Db.user.findOne ({author: "Wangwenlong"});For (var p = db.postings.find ({author:u.author});p. Hasnext;) {Printjson (P.next (). title); }2, Dbref Way AssociationExample:Step 1 Get current user informationDb.user.insert ({name: "Wangwenlong"})u1 = Db.user.find ({name: "Wangwenlong"}) [0]Step 2 post and associateDb.postings.insert ({"title": "Hello mongodb!"},users:[new dbref (' users ', u1._id)])
First, the demandUser answer, a total of 3, must be 3 questions are completed to submit.Objective: To query the user answered several questions correctly, answered several wrong questions. (Of course, you can only find the correct number of questions, with 3 minus the number of answers to the wrong question)Second, SQLSelect * from(Select Count(1) Rightcount from(Select * from(Select * fromMic_td_exercise_push_problem MPwheremp.push_id= 347 O
Label:Remember a very long SQL, in order to facilitate reading, I have added the paragraph: SELECT * from (
(SELECT 1 asAcheck, S1.id, S1.plan_name, S1.cost_mode, S1.sta_type, S1.cost_type, S1.cost_period_time, S1.cost_period_value, S1. ' Carrier_operator ', S1.cost_settle_type fromWo_serviceplan S1JOINWo_serviceplan_hotspot SH onS1.id=sh.serviceplan_idWHERES1.is_enable= 1 andsh.hotspot_id= 109 ORDER byS1.plan_nameASC )
UNION All
(SELECT 2 asAcheck, S2.id, S2.plan_name, S2.cost_m
Original source: http://blog.csdn.net/dba_huangzj/article/details/38657111, featured catalogue:http://blog.csdn.net/dba_huangzj/article/details/37906349 No person shall, without the consent of the author, be published in the form of "original" or used for commercial purposes, and I am not responsible for any legal liability. Previous article: http://blog.csdn.net/dba_huangzj/article/details/38656615 Objective: SQL Server has two types of authentication
A method of identity authentication based on secret information1. Password checkPassword check is the system for each legitimate user to establish a user name/password pair, when the user logged into the system or use a function, prompting the user to enter their own user name and password, the system by checking user input user name, password and the system has a legitimate user name/password pairs (these user names/ If the password matches the encry
Tags: ROC data structure min 3.x way iterator document blog MatFirst, it is clear that there is no difference between accessing the MONGOs and accessing the standalone Mongod. The next method is to access both the Mongod and the MONGOs. In addition, read Java to write Scala, anyway, everyone can understand ... Probably? 1. Connection method without authentication cluster (JAVAScala): The first is to create a connection method, we declare a client, and
ObjectiveWhether it is an ASP. NET MVC or Web API framework, the authentication of request information from the request to the response, and the authorization of the access page after the success of the authentication are extremely important, with two sections to focus on both, this section first tells some basic information about both, In the next section, we will deepen our understanding of the two throug
In keeping your servers and data secure from the current complex attacks, SQL Server has everything you need. But before you can effectively use these security features, you need to understand the threats you face and some basic security concepts. This article provides the basics so you can make the most of the security features in SQL Server without wasting time in the face of specific threats and the ability to protect your data.
Authentication is
This article compares the differences between the two.
Crawling
==============
MOSS and WSS3.0 are designed for Windows authentication. when MOSS was just released, there was no way to use the FBA (form based authentication) authentication method to crawl the network. in SP1, it includes the ability to set special crawling rules, allowing cookie-based
During installation, the SQL Server database engine is set to either Windows Authentication mode or SQL Server and Windows Authentication mode. This topic describes how to change the security mode after installation.If you select Windows Authentication mode during the installation process, the SA login is disabled. If you later change the
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