sql query builder

Distributed | data | database / * t-SQL code to implement distributed query of heterogeneous database using MS exec sp_addlinkedserver ' ms_sql ', ', ' SQLOLEDB ', ' 172.18.9.20 'exec sp_addlinkedsrvlogin ' Ms_sql ', ' false ', NULL, ' Sa ', ' capec '/* Create a remote link for SQL Server to SQL Server database * * ex

table [table name] Add field name the datetime default function increases the date Type field, where the function can be now (), date (), and so on, representing the default value (which is most commonly used, and other properties, which can be referenced by the following data type Delete field: ALTER TABLE [table name] Drop field name Modify size of variable-length text field: ALTER TABLE [table name] ALTER field name varchar (N) Delete table: drop tables [table name] Nbsp;

First SQL statementSelect CompanyName GSMC,ZB Zhibiao from Left Join T_companycode on T_GSNDZB.GSBH=T_companycode.companyidQuery Result:A second SQL statementSELECT min(CompanyName) GSMC,cast(round(sum(T_xstj.hsje)/10000,2) asNumeric -,2)) Ndje fromT_xstj Left JoinT_companycode onT_companycode.companyid=T_XSTJ.GSBHwhere DateDiff( YearSjgetdate())=0 Group byGsbhQuery Result:Statements that are merged int

Id = % d of the SQL query statement in PHP (recommended), SQL % d Some SQL statements are written as follows: 'Select id FROM dbname WHERE xx_id = % d; ', $ bl ['student _ id'] "Xx_id = % d", here % d Refers to a decimal number (d means decimal ), the content of the decimal number is the following $ bl ['student _ i

Read Catalogue Begin How SQL Server looks for records SQL Server Join method More specific execution procedures Index statistics: The choice of the query plan is based on Optimizing View Queries Recommended Reading-MSDN Articles For SQL Server optimizations, tuning queries can be a

Read SQL Server query planRead Catalogue Begin How SQL Server looks for records SQL Server Join method More specific execution procedures Index statistics: The choice of the query plan is based on Optimizing View Queries Recommended Reading-M

server| Speed | optimization MS SQL Server Query optimization method (1) There are many reasons for the slow query speed, common as follows: 1, no index or no index (this is the most common problem of query slow, is the defect of program design)2, I/O throughput is small, creating a bottleneck effect.3. No computed col

=n ' Ms_description ', @value =n ' table notes ', @level0typE=n ' SCHEMA ', @level0name =n ' dbo ', @level1type =n ' table ', @level1name =n ' name ' EXEC sp_updateextendedproperty @name =n ' Ms_ Description ', @value =n ' table Notes ', @level0type =n ' SCHEMA ', @level0name =n ' dbo ', @level1type =n ' table ', @level1name =n ' name '/*** Query comment Related sql***********************/--view table Comm

Enabling slow query log for tracking SQL Execution in MySQL and SQL log tracking in mysqlQuery slow query parametersShow variables like '% quer % '; Slow_query_log (whether to record slow queries) Slow_query_log_file (slow log file path) Long_query_time (logs are recorded only when the specified time is

Usage scenarios:For example, you need to query all student numbers with scores greater than 95, separated by commas into a string, from the Student score table.To prepare the test data:CREATE TABLE score (ID int,score int)INSERT into score values (1,90)INSERT into score values (2,96)INSERT into score values (3,99)It is now necessary to query the result string "2,,3" with a single statement.The

The more CPU and IO resources a query requires, the slower the query speed. Therefore, another way to describe the query performance tuning task is, the query command should be rewritten in a way that uses less CPU and IO resources. If the query can be completed in this way,

nested queriesShow the city's non-Shanghai staff information:SELECT * from staff where warehouse number in (select warehouse number from warehouse where city! = ' Shanghai ')Displays the average sales amount and warehouse number information for employees in different warehouses, provided that the average sales amount is greater than 15000 or the maximum sales amount is less than 18000 and the average wage of all employees is greater than 800 of the warehouse area:Select warehouse Number, AVG (a

the same, then the greater than and equals sign are the same)1.select gid,fariqi,neibuyonghu,reader,title from Tgongwen where fariqi> ' 2004-1-1 ' and fariqiSpents: 3280 milliseconds4. The date column will not slow down the query speed because there is a minute or seconds inputIn the following example, there are 1 million data, 500,000 data after January 1, 2004, but only two different dates, the date is accurate to the day, before the data 500,000,

Ind_attribute.is_ Disabled as [is disabled] 4 from (5 select Tab_name,index_name, [Co_names]=stuff ((SELECT ', ' +[co_name ') from 6 (select Tab. Name as Tab_name,ind. Name as index_name,col.name as Co_name from sys.indexes IND 7 INNER JOIN Sys.tables tab on Ind. object_id = tab.object_id and Ind.type in (8) inner join sys.index_columns index_columns on tab.object_id = Index_colu mns.object_id and ind.index_id = index_columns.index_id 9 inner join sys.columns Col on tab.object_id = col.object_i

1. SQL statements Is a language Meets ANSI standards Keyword cannot be abbreviated Use statements to control the definition information and data of tables in the database SQL is the abbreviation of Structured Query Language (Structured Query Language. You can use SQL statem

Original: SQL query performance analysisOriginal source: http://blog.csdn.net/dba_huangzj/article/details/7623926The performance of SQL query directly affects the value of the whole database, which must be treated solemnly.SQL Server provides a variety of tools, and here's a simple introduction:First, the

PDF browse: http://files.cnblogs.com/JimmyZhang/Linq-To-Sql-Part_3-Querying-our-Database.pdf Source:LINQ to SQL (part.3-querying our database)Glossary Built-in: built-inClause: ClauseDebugger: DebuggerObject Relational er Er: object link erORM (object relation mapping): object relationship ingVisualizer: ViewerPlug-in: plug-in programBreakpoint: breakpointShape: ConstructionObject initialization: object in

T-SQL query: CTE, T-SQL: CTE I have seen a simple example of the with as Clause in two books. I have not found any relevant information on the Internet. Summary: [Batch update of large tables] [Batch Delete large tables] [Keep only one row for completely repeated rows] -- Create a test TABLE -- drop table [tabName] SELECT * INTO [tabName] FROM sys. objectsSELEC

Label:1. View the user tableSelect from Sys.tables Select from where type='U' Select from where xtype='U' where type or xtype value:U = user table S = system table V = view FN = scalar function TF = table function P = stored procedure TR = Trigger 　　D = defaults or Default constraints PK = PRIMARY KEY constraintF = FOREIGN KEY constraint UQ = UNIQUE constraint SELECT from Information_schema. TABLES2. View ViewSELECT * from Information_schema. Views3. View the table/view fieldsS

Part i:relational Databases and SQLChapter2, ensuring Your Database Structureis sound.Database Design GuidelinesWhat is a relational databaseRDBMS (A relational database management systems) relational databaseTablesTables is the mainstructures in the database. Each table always represents aSingle, Specificsubject.FieldsA field is thesmallest structure in the database, and it represents a characteristicof the subject ofthe table to which it belongs.RecordsA record Representsa unique instance of t