sql fetch first 1 row only

I. Introduction of row migration and row link in actual work we often encounter some problems with low Oracle database performance. Of course, there are many reasons that cause low Oracle database performance, we can use some correct design and

Recently in the analysis of the new features of offset and fetch in SQL Server 2012, it is quite good to find that the offset and fetch, whether the syntax is concise or powerful, are fairlyWhich offset and fetch the most important new features are

Reference article:Http://www.williamsang.com/archives/1508.htmlScenario BriefThe school records the results, each person's choice course is different, and later will add the course, so do not need to take all the courses as a column. Database grade

Original: http://ntk2006.blog.sohu.com/135331235.html Cursor ConceptCursors provide a flexible way to retrieve and operate data from tables. cursors are mainly used on servers to process SQL statements sent from clients to servers, or data

Row chain: When a row is too large to fit into any block, row chaining occurs. in this case, the Oracle devide the row into smaller chunks. each Chunk is stored in a block along with the necessary poiters to retrive and assemble the entire row.

MS SQL Server Query optimization methodThere are many reasons for the slow speed of queries, which are common1, no indexes, or no indexes (this is the most common problem with query slowness, is the flaw in programming)2, I/o throughput is small,

I am a novice, there is a problem please help, is to use the Mysqli class, the data table test has 5 rows of data, with the Foreach function can only take out the first row, the others are not taken out, while using while can be removed 5 rows, why?

Row migrations and row links lead to degraded Oracle performance, this article describes what row migration and row links are, what they do, how to judge them, and provides solutions to them.What is row migration and row link row migrationOracle's

*sql optimization based on ORACLE11GR2 reading notes * Third, cursor in OracleThe cursor in Oracle is a vector of SQL parsing and execution in an Oracle database and is a data structure for C (Oracle is written in C).There are two types of cursor in

I. cursor Recognition Cursor allows you to access the result set returned by SQL Server row by row.A major reason for using cursor is to convert the set operation into a single record processing method.After retrieving data from a database using