sql query executed successfully but no results

To analyze the performance of a query, you can view {Tagshow (event, '% D6 % B4 % D0 % D0 % BC % C6 % BB % AE ');} "Href =" javascript:; "target =" _ Self ">Execution Plan. Execution Plan description {Tagshow (event, 'SQL ');} "Href =" javascript:; "

An explanation of the SQL statement execution Process 2014-07-17 01:15:43Category: OracleAn explanation of the SQL statement execution processa pieceHow is the execution of Sql,plsql executed?First,SQL statement Execution principle:The first step:

Today to see a Bo Friends of the article, feel good, reprint, hope to help you, more articles, please visit: http://blog.haoitsoft.com1, no index or no index (this is the most common problem of slow query, is the defect of program design)2, I/O

1. Union, except T, Intersect Operators A, Union operator The Union operator combines two other result tables (such as Table1 and table2) and removes any duplicate rows from the table to generate a result table. When all is used together with Union (

Document directory   Keywords: SQL Research Keywords: SQL study 1. Union, except T, Intersect Operator A, Union operator The Union operator combines two other result tables (such as Table1 and table2) and removes any duplicate rows from the

Many of my friends may be making mistakes in performance optimization as described below. If you have any need, please refer to the mistakes in SQL Server query performance optimization to get out of the index. Many of my friends may be making

Directory1. What is an execution plan? The information on which the execution plan depends.2. Unify SQL statement writing to Reduce parsing overhead3. Reduce SQL statement nesting4. Use "temporary table" to save intermediate results5. The SQL

It is understood that the vast majority of developers have a thorough understanding of indexing, limited to the fact that most daily work has no chance, and there is no need to care about or understand indexing, when a query is too slow, you can

SQL statement optimization improves database performance and SQL statement database performance In systems with unsatisfactory performance, apart from the fact that the application load exceeds the server's actual processing capacity, it is more

About buffered queries and no buffer queriesThere are two types of queries for MySQL clients:buffered queries: will receive the results of the query and store them in the client's cache, and the request to obtain row records is only obtained locally.