how to tune sql query

Label: Rest Data Service Query class Need Iserver data service support, but when requested, do not rely on Supermap js Lib package. constructor :Querybyid=function(p_params); p_params={}; The specific parameters are described as follows: p_params. 　　　　　　URL; //Http://127.0.0.1:8090/iserver/services/data-China400/rest/data/featureResults.json p_params. 　　DataSets; //world:captitals,world:captitals,world:captitals p_params. 　　Callback; ca

Tags: _id repos query Statement automatic learning experience query logs SQL definitionFirst, in the @entity annotated class to write a good foreign key relationship.This @ManyToOne annotation can establish a foreign key relationship, not in their own silly write a private int grades_id; After writing this note, it automatically adds the Classes table to the grad

Label:--sal for employee wagesSELECT * from EMP;--Inquire about employee information in the [1500,3000] range of wagesSELECT * from emp where Sal >= and Sal SELECT * from EMP where Sal between and 3000;--The above two sentences have the same effect--Query employee information for wages less than 1500 or greater than 3000SELECT * from emp where Sal SELECT * from emp where Sal is not between and 3000;--The above two sentences have the same effect--

Document directory SQL group by syntax SQL having syntax Ii. Aggregate functions and group queries 1. Aggregate functions Common Aggregate functions include AVG (all/distinct field name), count (all/distinct field name), max (field name), min (field name), and sum (field name) 2. query groupsGroup by statement The group by statement is used in combination w

=Bumen.code - --three keywords before--------join on------------- the --If two tables do not have a primary foreign key relationship, only two tables are displayed if the keyword is not added before the join - -- Full - --add full before join to display all information for two tables (including information not in two tables) - SelectBiao2.name,sex,age,bumen.name,zhineng,ceo fromBiao2 + Full JoinBumen onBiao2.bumen=Bumen.code - -- Left + --add left before join to show all the information (includ

If the month is the current month minus the time you want to calculate, for example, to query all records in the database for the first three months from today, our statement is as follows: mktime (date (\ 'H \ '), date (\' I \ '), date (\'s \'), date (\'m \ ')-3, date (\ 'd \ '), date (\ 'y \'); mktime (date (\ 'H \ ') within seven days \'), date (\ 'I \'), date (\'s \ '), date (\'m \'), date (\ 'd \ ')-7, date (\ 'y \')); Mysql tutorial

Tags: value pos ble table ali relational fuzzy query float precisionExact query:sql:field= "Value"mongo:{"field": "Value"}---------------------------------Fuzzy query: Match on both sides Right match Left match Sql: Field= "%value%" Field= "Value%" Field= "%value" Mongo: {"Field":/

http://blog.csdn.net/sxdtzhaoxinguo/article/details/51481430Abstract: MySQL database implementation of paged query SQL statement writing!One: Paging needs:The client passes the start (page number), limit (number of bars per page) two parameters to page through the data in the database table, then we know that the MySQL database provides paging function limit m,n, but the use of this function is different fr

Label:SELECT B.deptname,A.badgenumber,A.userid,A.SSN,A.nameFROM dbo. USERINFO AINNER JOIN dbo. Departments B on a.defaultdeptid = B.deptidWHERE A.SSN is not NULLAnd b.deptid like '% ' Table ' USERINFO '. Scan count 1, logic read 278 times, physical read 0 times, pre-read 0 times.Table ' departments '. Scan count 1, logic read 4 times, physical read 0 times, pre-read 0 times. SQL Server Execution Time:CPU time = 15 milliseconds, time-consuming = 54 mil

Php:It is usually the beginning of the code you want to check to record a time, the end of the record a time. Take the difference value,the efficiency of database SQLSQL explain (MySQL), enable slow query log to record slow queries. Usually also depends on the database design is reasonable, the demand is reasonable and so on.But this time is generally very fast, in less than a second, so you can not directly use mktime ()function Getmicrotime () {Lis

Tags: reading Notes database sql Part iii:thinking in SetsCHAPTER7 Thinking in Sets The three Mostcommon set operations is as follows. Intersection Difference Union in the SQL The corresponding keywords in each of the Intersection Except Union The actual database implementation generally supports the following

Query, delete, insert, query, and sort SQL statementsHere we provide the maximum and minimum SQL statements for queries, deletions, inserts, queries, total sorting sum and average.Select: select * from table1 where rangeInsert: insert into table1 (field1, field2) values (value1, value2)Delete: delete from table1 where

;--current session process ID SELECT @ @textSize; SELECT @ @version;--Current database version information 9. System Statistic function SELECT @ @CONNECTIONS;--Number of connections SELECT @ @PACK_RECEIVED; SELECT @ @CPU_BUSY; SELECT @ @PACK_SENT; SELECT @ @TIMETICKS; SELECT @ @IDLE; SELECT @ @TOTAL_ERRORS; SELECT @ @IO_BUSY; SELECT @ @TOTAL_READ;--Read disk count SELECT @ @PACKET_ERRORS;--Number of network packet errors that occurred SELECT @ @TOTAL_WRITE;--sqlserver the number of disk writes p

All right, go to the database log to search for it and use the time and keyword for batch configuration .. You can use all that you can think.First, assume that you have executed it. No? Okay, either it's too simple, or you're too simple ..Copy codeThe Code is as follows:Select top 1000-- Creation TimeQS. creation_time,-- Query statementSUBSTRING (ST. text, (QS. statement_start_offset/2) + 1,(Case qs. statement_end_offset WHEN-1 then datalength (st. t

Fuzzy query and SQL fuzzy query Public function Index () {// fuzzy query by account, real name, and mobile phone number $ user = M ('cuser'); $ where = "(IFNULL (projectno ,'". session ("user") ['projectno']. "') = '". session ("user") ['projectno']. "'OR projectno ='') "; if (! Empty (I ('Param. name ') {$ name = trim

Users use email as a user name landing, you need to check out an email corresponding to a record. Each user's email is unique.SELECT * from T_user WHERE email=?;The above statement implements a query email corresponding to a user information, but because the email column is not indexed , will result in a full table scan , the efficiency will be very low.SELECT * from T_user WHERE email=? LIMIT 1;Plus limit 1, as long as a corresponding record is found

Table:Reseller Dealer Field UID Parent_uid nameContact Contacts Field UID dealer_id contact_mainDemand:Want to inquire about the reseller's information, and the main contact information of this reseller, and the reseller's parent reseller's nameCaseThere may be parent_id that are nullSQL statements: SELECT dea.uid uid, dea.enabled_flag enabledflag, dea.delete_flag Deleteflag, dea.tenement_id Tenementid, dea.parent_id parentid, pd.name parentname,

Select A.name as table name, b.name as column name, c.name as type, b.max_length as Byte count, b.precision As Integer, B.scale as decimal from Sys.tables a INNER JOIN Sys.columns B on a.object_id=b.object_id inner join Sys. Types C on c.user_type_id=b.user_type_idThis article is from the "IT" blog, so be sure to keep this source http://8577754.blog.51cto.com/8567754/1553205How to use a statement in an SQL query