truncate statement in sql

Today, I occasionally see the with keyword in SQL. I have been writing SQL statements for a few years, so I was the first to get in touch with it. After reading an article by a blogger, I added some content and made a simple summary. This statement was the first time I saw and learned. From simple to complex writing, I hope the experts will not laugh. The followi

Tags: optimize order bar including result group default MySQL selOriginal: http://bbs.landingbj.com/t-0-243202-1.htmlBy default, MySQL sorts all group by col1, Col2, ...., and the method of querying is like specifying order by col1, col2, ... in a query.If you explicitly include an ORDER BY clause that contains the same column, MySQL can optimize it without slowing down, although it is still sorted.If the query includes group by but you want to avoid the consumption of sort results, you can spec

--(' table ', ' line ', ' ods_xx ') all the tables and users in this case need to be capitalized.If the table name user name is not written, the error is reported: the object "EMP" is of type table, not found in the scheme "Scott"Pro-Test code:Set long 90000;Set Linesize 4000;Set pagesize 4000;Spool Table.sqlSelect Dbms_metadata.get_ddl (' TABLE ', ' line ', ' ods_xx ') from dual;Spool off1, once want to query the table additional log: dbms_metadata.get_ddl (' table ', ' name ', ' User name ') f

Tags: add query Insert ignore local select SQL ROM batchWay 1:insert into T1 (field1,field2) VALUE (' 001 ', ' 002 '); The best practice is to explicitly insert each column, listed in the error, and the chance of missing the column will be reduced! Way 2:insert into T1 (field1,field2) VALUES (' 001 ', ' 002 '), (' 003 ', ' 004 ') ...; It is best to bulk insert data in bulk, but when the data is too large, it is best to BULK insert in batches! Way 3:

Max (param_value) from Ods_yx.sys_param_value v where v.gdjdm= ' 040100 ' and V.param_code=t2.self_supply_modeand v.param_type_code= ' Self_supply_mode ') power supply modeFrom Ods_yx.user_files T1,ods_yx.power_file T2 where T1.user_no=t2.user_no andT1.business_place_code in (#) and t1.user_stateand T2.self_supply_mode in (' 5 ', ' 6 ')7. Production MIS system parameter informationSelect Ywbm,nr from pd_gy_sbzdb where sjbm= ' 5012 ' device status--Distribution Station informationSELECT * from P

performance of the two-range query with YY_BH Index is certainly greatly improved.9. Appropriate and inappropriate in the query conditionsQuery parameters can include actions: =, Inappropriate query parameters are: not,! =, 10. Use Delete sparinglyIn general, some of the logic of deleting data will be implemented more or less in stored procedures. For a small number of tables, the problem is not very big. But for large data tables, deleting data with delete can have a certain effect on the perf

//Method One, you can verify the login, but the method is not practical.PackageCom.swift;Importjava.sql.Connection;ImportJava.sql.DriverManager;ImportJava.sql.ResultSet;Importjava.sql.SQLException;Importjava.sql.Statement;Importjava.util.ArrayList;Importjava.util.List; Public classLOGINJDBC { Public Static voidMain (string[] args) {User Userzhangsan=NewUser ("Swift", "123456"); if(Login (Userzhangsan)) {System.out.println ("Successful Landing"); }Else{System.out.println ("Login Failed"); } }

Label:More than 5 o'clock in the evening, colleagues in QQ told me that a user responded to him, when he logged in to display the error message, we in the management platform to view the user's basic information, also display error message. After a preliminary analysis, an int overflow occurred while executing the SQL statement: sql = "Select sum (fileSize) as Fs

PHP failed to execute SQL statement, but the same statement can be executed in MySQL The problem now is that some tables in the same database can be queried, and some tables cannot be queried. But these statements can be executed in MySQL correctly. ------Solution-------------------- A situation of a situation check, LZ can be combined in PHP over the

Beckham _ mysql SQL statement optimization process, Beckham _ mysqlsql statementSQL statement OptimizationI. general steps for SQL Optimization (1) Use the show status command to understand the execution frequency of various SQL statements. (2) locate

During this time, writing of LINQ and SQL is missing! Or are you getting old? More and more will not change Problem: ========================================================== ======== VaR ret = from X in LSWhere (String. isnullorempty (Arg. querytext )? True:((X. ?? ""). Toupper (). Contains (Arg. querytext. toupper ())| (X. B ?? ""). Toupper (). Contains (Arg. querytext. toupper ())| (X. c ?? ""). Toupper (). Contains (Arg. querytext. toupper ()))I

Many people do not know how SQL statements are executed in SQL Server, fearing that their written SQL statements will be misunderstood by SQL Server. Like what: SELECT * FROM table1 where name= ' Zhangsan ' and TID > 10000 and implementation: SELECT * FROM table1 where TID > 10000 and name= ' Zhangsan ' Some people

SQL--MYSQL query statement Daquan, sqlmysql statement 1: Use the SHOW statement to find out the current database on the server: Mysql> show databases; 2. Create a database named MYSQLDATA Mysql> create database mysqldata; 3: select the database you created Mysql> use mysqldata; (when you press the Enter key to see Data

Data update table names can be updated at one time set Colnum1=value1,colnum2=value2,... where condition eg:sql > Update t1 set ename=joke , Sal=3000 where empno=7782 ; DELETE statement -- Delete data from table (table is always present) from table name where condition from where empno=7782; truncate statement

MySQL uses the SQL statement TRUNCATETABLE to quickly clear the data of a data table, so that the data table is cleared without retaining logs. Although TRUNCATETABLE is the same as a DELETE statement without WHERE, TRUNCATETABLE is faster and consumes less resources. TRUNCATETABLE does not record logs, so it cannot be excited. MySQL uses the

ArticleDirectory In the SQL statement, the as statement can have the same name as the front field. In the SQL statement, the as statement can be the same as the preceding field: Select *, CaseMycolumnnameWhen '0' then' out

Tags: obj tail string nbsp Declare put comment out set /************************************************************************************************************** **************************************** Dynamic statement syntax: Exec/sp_executesql syntax Finishing Man: China Wind (Roy) Date: 2008.06.06 *************************************************************************************************************** *********

"The latest X of every Y" is a classic SQL problem that is frequently encountered at work. Of course, it is not as simple as "querying the latest X value by Y Group". It requires the record or primary key ID of the latest X. You can use an SQL statement to solve this problem. Generate instance tables and data: "The latest X of every Y" is a classic

Question one: The difference between statement and PreparedStatementFirst of all, what is statement in Java:statement is an important way for Java to perform database operations to send SQL statements to the database, based on the database connection that has been established. Specific steps:1. First import java.sql.*; this package.2. Then load the driver, create

shows that the syntax of the subquery statement is not checked, but filtering plays a role, which is indeed a strange thing. If I mistakenly typed select xid in select * from tb1 where id in (select xid from tb2) into select id when I typed an SQL statement, then there will be a problem with the Retrieved Data (full extraction), but there is no prompt, because t