sql query cheat sheet

IOS Application Security testing Cheat Sheet[Hide] 1 DRAFT CHEAT sheet-work in PROGRESS 2 Introduction 3 information gathering 4 Application Traffic analysis 5 Runtime Analysis 6 Insecure Data storage 7 Tools 8 related articles 9 Authors and Primary Editors Ten other cheatsheets DRAFT

Tags: statement upd dealloc ace http int form Insert backPostgreSQL Cheat Sheet CREATE DATABASEDbName;CREATE TABLE (with auto numbering integer ID)TableName ( ID serial PRIMARY KEY, name varchar () UNIQUE not NULL, dateCreated timestamp DEFAULT current_timestampADD a primary keyTableName ADD PRIMARY KEY (ID);Create an INDEXIndexName On TableName (ColumnNames);Backup a Database(command line) DbName dbName

|Sort-z# toFindFiles Bigger Thank2MB and list them:Find. -type f-size +20000k-execls-LH {} \; |awk '{print $9 ":" $ $}'# toFindFiles Modified Morethan7Days ago and ListfileInformationFind. -type F-mtime +7d-ls# toFindSymlinks owned by a user and listfileInformationFind. -type L--user=username-ls# to search forand Delete empty directoriesFind. -type d-empty-execrmdir{} \;# to search forDirectories named build at a max depth of2DirectoriesFind. -maxdepth2-name Build-type d# to search all filesW.H

conflict will be prompted when saving. Verification Success!Create a ViewSelect the database, right-click the View node, select New ViewIn the Add Table window, click on the Product table, click Add, the Query window appears a view of the product table, and then click Close.Then the query window click need to show the "Product Name", "brand", "Price", click the Execute button, you can display the table inf

In a new environment to develop, with PL/SQL to connect the database, open one of the tables when the report "Ora-29275:partial multibyte character" error. Look carefully, the data in this table are all kinds of garbled characters.Online search information, said anything, but basically is only applicable to their situation at the time of the special case. The final analysis is that the character set format of the attached database is the same as the l

, last_number from User_sequences; SELECT Invoice_seq. Currval,invoice_seq. Nextval from DUAL; SELECT Invoice_seq. Currval from DUAL; SELECT Invoice_seq. Currval,invoice_seq. Nextval from DUAL; CREATE TABLE Invoice (invoice_id number PRIMARY KEY,--auto-numbered, unique, not empty vendor_id # NOT NULL, --Vendor ID Invoice_number VARCHAR2 () not NULL,--Invoice number Invo Ice_date Date DEFAULT sysdate,--Invoice date

[Zhuantang learning notes] basic SQL query statements (single-Table query and multi-Table query)SQLQueryBasic1. Single Table query It is also called projection. Basic query statement Structure Select column from table * Not all ot

50 SQL Query Techniques, query statement examples, 50 SQL statements Student (S #, Sname, Sage, Ssex) Student tableCourse (C #, Cname, T #) CurriculumSC (S #, C #, score) Orders tableTeacher (T #, Tname) Instructor tableProblem:1. query the student ID of all students whose s

data, the same query in different circumstances may produce the opposite result, how to apply well is mainly in our personal understanding and understanding, hope to see this article friends can deepen some understanding of the index and understanding , and get rid of the error of index and develop high performance application. I am not a DBA, just a common developer, the above are some of the actual work experience, experience, in view of my level i

than the number of rows of data The statements and data used in the example are used only as demos, the actual development application is more complex than the sample data, the same query in different circumstances may produce the opposite result, how to apply well is mainly in our personal understanding and understanding, hope to see this article friends can deepen some understanding of the index and understanding , and get rid of the error of in

level is very limited, there is said wrong or understanding not in place also hope that the great God to correct, lest mislead others, greatly appreciated.Follow-up will continue to write some practical experience in SQL Server query performance optimization, mainly include the following aspectsSQL Server query performance optimization to establish a reasonable

id>=, the other is to use join, to see the actual situation: SELECT * FROM Product WHERE ID > = (select ID from Product limit 866613, 1) limit 20Query time is 0.2 seconds, is a qualitative leap ah, haha Another way of writing select * from Product a joins (select ID from product limit 866613, +) b on a.id = b.ID query time is also very short, like! In fact, both use a principle, so the effect is similar Execution plan Explain +

Know "query analyzer" Start the Service Manager and open the Enterprise Manager. Select the database to be operated (taking my sky2098 as an example), and select "SQL query analyzer" in "Tools" on the menu bar ": If the "Object Browser" on the left is not displayed, you can do this: Select the "Tools" tab on the toolbar and select the "show/hide" option in the e

102 Lucy 18 Shanghai 11 Professional Information Sheet (majors): Id Name 10 中文版 12 Computer Preset script:DELETE from Studentsinsert to Students (Id,name,age,city,majorid) VALUES (101, ' Tom ', +, ' Beijing ', ten) INSERT into Students (Id,name,age,city,majorid) VALUES (102, ' Lucy ', and ' Shanghai ', one) DELETE from Majorsinsert to

This tutorial for you to introduce the SQL of the multiple table query, let's look at the specific examples. Create a new two sheet: Table 1:student screenshot as follows: Table 2:course screenshot as follows: (This is just a table to demonstrate the connection of SQL statements, of course, in the actual develo