tuning oracle sql queries

Oracle queries the first 10 records and paging queries (5th to 10th records), and oracle queries the first 10 records If you want to know the actual application solutions of the first 10 records in Oracle query, you can click the

,TbWHERE TB.QJ = my1.qj + 1)SELECT *From My1SQLserver2008 using an expression recursive query--recursively subordinate by parentWith CTE (Id,parentid,text)As(--Parent itemSelect Id,parentid,text from treeview where ParentID = 450UNION ALL--Subordinates in recursive result setsSelect T.id,t.parentid,t.text from TreeView as TINNER join CTE as C on t.parentid = C.id)Select Id,parentid,text from CTE-----------------------Child recursive parentWith CTE (Id,parentid,text)As(--Subordinate parentSelect

Three ways to "SQL" Oracle Paging queriesUse pseudo-column rownum to query the first 10 records? 1234567891011 [sql] select * from t_user t where ROWNUM 按照学生ID排名，抓取前三条记录[java] SELECT * FROM(SELECT id,realname FROM T_USER ORDER BY id asc ) WHERE ROWNUM 分页SQL写法，从第10条记录开始，提取10条记录。[java] SELECT * FROM (SEL

of records can have a layer number because the nodes are in different hierarchical locations. The layer number is determined by the distance between the node and the root node. The starting root node is always 1, the child node of the root node is 2, and so on, regardless of which node it starts from.5. Cropping of nodes and branchesWhen querying a tree structure, you can remove some rows from the table, or you can cut out a branch in the tree, and use the WHERE clause to qualify a single node

Tags: database 2008R2 obs Soft technology Share right-click String key Error1. Create dblink for Oracle databases in SQL Server as you would for Oracle databasesSecurity is also defined (seemingly no need to follow the access string only need to fill in one)Direct query error, need to change registry add optionkey 1 , rename the newly added item to "OraOLEDB.Orac

dramatically improve the performance of SQL statements with a few simple SQL tuning rules. --Adjusting Oracle sorting: Sorting has a significant impact on Oracle performance. --Adjust Oracle's competition: Table and index parameter settings have a significant impact on the

you can dramatically improve the performance of SQL statements with a few simple SQL tuning rules. --Adjusting Oracle sorting: Sorting has a significant impact on Oracle performance. --Adjust Oracle's competition: Table and index parameter settings have a significant impa

tuning, and it's not surprising that you can dramatically improve the performance of SQL statements with simple SQL tuning rules. --Adjusting Oracle sorting: Sorting has a significant impact on Oracle performance. We begin by adj

in 10g, Oracle launched its own SQL optimization aids : SQL Optimizer (SQL Tuning Advisor :STA) , it is the new Dbms_sqltune package. Use the STA to make sure that the optimizer is in CBO mode. but I think that using this tool is only suitable for people who don't understa

Tags: sql OracleUpdating a field is simple and easy to understand: Update TableA A SET a.name= (select name from TableB B where a.id=b.id) is more verbose when updating multiple fields: UPDATE TableA A SET a.name= (select name from TableB b where a.id=b.id), a.age= (select age from TableB b where a.id=b.id) If you need to update too many fields, so the write is too messy, and the efficiency of duplicate query is also greatly reduced, you can use t

Tags: sql serveroraclemybatismysqldb2 Like fuzzy queries for Oracle, MySQL, DB2, SQL Server in MyBatis

that you can dramatically improve the performance of SQL statements with a few simple SQL tuning rules. -- Adjust Oracle Sorting: Sorting has a significant impact on Oracle performance as well. -- aligning Oracle's competition: Table and index parameter settings have a

minscopeFrom Test T,(Select A.type, max (a.scope) maxscope, Min (a.scope) minscopeFrom TEST AGroup by A.type) dwhere T.type = D.type--min ()/max () over (partition by ...)Select T.*,NVL (Max (t.scope) over (partition by T.type), 0)-T.scope maxscope,T.SCOPE-NVL (min (t.scope) over (partition by T.type), 0) MinscopeFrom Test T--lead ()/lag () over (partition by ...)Select T.*,lead (t.scope,1,0) over (partition by T.type ORDER by T.scope) a--the same group after oneFrom Test TSelect T.*,lag (t.sco

ofSelectS.sname name, c.cname name, T.score score +5 fromStudent S,course C,score Twheres.s# School Number =t.s# No. andC.c# Course Number =t.c# Course No. andS.grade grade =' " andt.c# Course Number =' 2 ' 7.Number of people born in the same monthSelect Count(To_char (difdate Birth date,' mm ')) fromStudentGroup byTo_char (difdate date of birth,' mm ')8.Delete Name is Zhang San's University language achievementDelete fromScorewheres# number =' 2008020177 ' andC # Course Number =' 3 ' 9.T

increase the simultaneous processing capacity Determine earnings Determine cost Monitoring tasks with common bottlenecks Monitor memory usage Monitor thread and CPU usage Monitor hard disk I/O Monitor low-performance queries Monitor stored procedures, SQL, and user activities Monitor current locks and user interactions Create a performance tuning