how to tune sql query

SQL paging query Stored Procedure Code sharing, SQL stored procedure For more information, see the code. ---------------------------------------- Author: Zhang Xinyu ----- time: 2013-06-28 ----- Introduction: query by parameters and conditions by PAGE ------------------------------------- Create proc [dbo]. [Up_PagingQ

In SQL ServerEach database has a table generated by the system.The table sysobjects records all the table names in the database.We can use the following SQL syntax for query operations. Copy codeThe Code is as follows:Select Name, id from sysobjects where xtype = 'U' Xtype = 'U' indicates the table used. If xtype = 's' is used'The default table There is also a

Check this diary record SELECT * FROM Messages WHERE convert (Nvarchar, createdate, MR) = CONVERT (Nvarchar, GETDATE (),) Order by CreateD Ate DESC SELECT * from table WHERE DateDiff (day, column name , GETDATE ()) =0 Check this year SELECT Count (*) from Messages WHERE DateDiff (year,createdate,getdate ()) =0 Query this month SELECT Count (*) from Messages WHERE DateDiff (month,createdate,getdate ()) =0 This week 's record SELECT * from

An additional column of serial numbers is automatically added to the SQL statement query results, and an SQL column is automatically added. Sqlserver It can be implemented using the row_number function. As follows: SELECT *, row_number () OVER (order by score (column name) DESC) AS rank FROM score The SQL

a joins Dept b on (a.deptno = B.deptno) Order BY empno Desc;To sort by an alias of a field or an expressionSelect A.ename,a.mgr,a.empno, (a.sal*12) as annsal from EMP a order by annsal;1.5 GroupingSelect B.deptno,b.dname,sum (a.sal)From EMP a,dept bwhere A.deptno=b.deptnoGROUP BY B.deptno,b.dnameORDER BY B.deptno DescFields after GROUP by = ALL display fields except aggregate functions in the select listThe total wage, the number of people, the maximum wage, the minimum wage, the average wage o

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;

The SQL statement is used to query the Index usage and the index status of the SQL statement. SELECT sch.name + '.' + t.name AS [Table Name], i.name AS[Index Name], i.type_desc, ISNULL(user_updates,0) AS [Total Writes], ISNULL(user_seeks +user_scans + user_lookups,0) AS [Total Reads], s.last_user_seek, s.last_user_scan , s.last_user_lookup, ISN

This issue is especially important for projects with a relatively large scale. If there are hundreds of stored procedures in the database,I can't find them one by one. Even if I understand the business and system very well, it will take a long time to remember.How can I use SQL statements for queries?The following describes how to query SQL statements:Copy codeTh

--Find all parent nodesWith TAB as(Select Type_id,parentid,type_name from sys_paramtype_v2_0 where type_id=316--child nodesUNION ALLSelect B.type_id,b.parentid,b.type_nameFromtab a,--child node datasetsSys_paramtype_v2_0 B--parent node data setWhere a.parentid=b.type_id--the child node DataSet. Parendid= The parent node data set. Id)SELECT * from tab;--Find all child nodesWith TAB as(Select Type_id,parentid,type_name from sys_paramtype_v2_0 where type_id=1--parent nodeUNION ALLSelect B.type_id,b

Tags: style time span stat name not sel tab DUPI'm using a statement to save the queried data to a new table 1) using the into table statement, the new table that needs to be saved does not need to be created in advance Select * to from table-Insert new Table statement into TableName 2) using the Insert Table statement, the new table that needs to be saved does not need to be created in advance CREATE TABLE [dbo].[newtable]( [Fdsequenceid][bigint] not NULL, [Fdinnertime][Da

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

SELECT type,--clerk type sum (virtual_memory_reserved_kb) as vm_reserved_kb,--reserved Memory sum (VIRTUAL_MEMORY_COMMITTED_KB) as VM_COMMITTED_KB,--committed memory sum (awe_allocated_kb) as awe_allocated_kb,--the memory sum (shared_memory_reserved_kb) as SM used when opening awe _RESERVED_KB,--shared reserved memory sum (shared_memory_committed_kb) as sm_committed_kb,--shared commit memory sum (single_pages_kb) as SINLGEPAGE_KB,--Buffer pool stolen Memory sum (multi_pages_kb) as multipage_kb--

=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

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