how to optimize sql query using execution plan

SQL data query optimization select nbsp;. id, rkno,. packageno nbsp; as nbsp; packageno, cust_no, lotno, count (*) nbsp; as nbsp; count nbsp; from nbsp; 'rk _ record ' nbsp; as nbsp; a nbsp; right nbsp; join nbsp;'s SQL data query optimization Select. id, rkno,. packageno as packageno, cust_no, lotno, count

In most cases, upgrading your database to SQL Server 2008 can improve query performance. However, if you have mission-critical queries that have been carefully optimized for performance, it is a good idea to create a planning guide for each query before you upgrade to keep the query plans for those queries. If, after t

query optimization, directly use table scanning. View execution information ,:Table 'News '. Scan count 1, logical reads 342, physical reads 0, pre-reads 0, lob logic reads 0, lob physical reads 0, and lob pre-reads 0.(Row 3 is affected)(One row is affected)(40 rows affected)Table '# tb ________________________________________ 20170004c024 '. Scan count 1, logical reads 257, physical reads 0, pre-reads 0,

greater than a certain threshold, and uses table scans directly. Look at the execution information: Table ' News '. Scan count 1, logical read 342 times, physical read 0 times, read 0 times, LOB logic read 0 times, lob physical read 0 times, lob read 0 times. (98361 rows affected) (1 rows affected) (40 rows affected) Table ' #tb________________________________________00000004C024 '. Scan count 1, logical read 257 times, physical read 0 times, read 0

Label: explanatory vs. Pre-compiled 1, the traditional database, stored procedures have comp process, IQ does not do. 2,!!! Stored procedure performance throughput is halved compared to direct queries. 3, within the IQ, multiple statements will be analyzed and converted into stored procedures to execute. So the statement executes more than once, and the statement executes less directly. 4. Using the index Simplified conditions Select algorithm

Recently and colleagues to deal with a small program, the data volume is not particularly large, a table of data records: 7000W records around, but from the change to execute a query, but found that the query is not fast, and the most obvious problem is cpu100%.SQL statements:Select from where LNG> and LNG and lat> and LatMax_lat;To find the problem, use the fol

Using Merge INTO to optimize SQL greatly improves performanceBackground: There is a need for development. You need to update data for a newly added field based on the specific business logic.The TPS_TRADE table contains more than 40 million data, TPS_EXTERNAL_REF table more than 36 million, and TPS_ACCOUNT table more than 82 million.The developed

This article transferred from: http://www.cnblogs.com/hnsdwhl/archive/2011/07/23/2114730.htmlWhen it is necessary to determine the SQL statement to execute based on the parameters of the external input, it is often necessary to construct SQL query statements dynamically, which is more commonly used by the paging stored procedure and the

Label:When it is necessary to determine the SQL statement to execute based on the parameters of the external input, it is often necessary to construct SQL query statements dynamically, which is more commonly used by the paging stored procedure and the SQL statement that executes the search

[Author]: KwuUsing subqueries to optimize the SQL for hiveExecute a simple statement in 100 million data to query the number of users who only visit the primary site at a time:Select COUNT (*) as CNT from Tracklog GROUP by Cookieid have cnt=1;Query response is slow, half an hour is not the resultOptimizing Hive-

SQL format execution sequence of oracle data structure and sequence number of SQL query processing, oraclesql I. execution sequence of SQL format FROM-> WHERE-> group by-> HAVING-> SELECT-> ORDER 1. The from clause assembles data

QQ, a buddy, asked me how to optimize this SQL statement. It takes 160 seconds. SQL> explain Plan for select. so_region_code, 2. so_county_code, 3. so_org_id, 4 d.org _ type_id org_type_id, 5. op_id, 6 nvl (C. brand, 0) Brand, 7 E. res_code, 8. busi_code, 9. so_nbr, 10 decode (. isnormal, 11 2, 12-count (distinct. so_n