SQL is a set-based language, meaning operations are completed on all or rows of the result. However, there are times, when you want to do operation on a row by row basis. This is where cursors come in to play.
Learn what is Cursor in SQL with the help of examples. SQL cursor is a database object that is used to manipulate and traverse the result set of a SELECT query.
DECLARE My_Cursor CURSOR --定义游标 FOR (SELECT jid FROM journal WHERE isall in(1,2)) --查出需要的集合放到游标中 OPEN My_Cursor; --打开游标 FETCH NEXT FROM My_Cursor INTO @jid; --读取第一行数据 WHILE @@FETCH_STATUS = 0 BEGIN SET @pic=(SELECT TOP 1 smallpic FROM journalissue WHE...
If you want to link SQL tables to individual records, making your database much more efficient and responsive, then you will need knowledge of...
Let's build a query based on the sample data. We want to select albums that have a rating of 9 or above. In plain terms, we are asking the following of the database: Give us album titles from the database, where the rating is greater than or equal to 9. In SQL, we actually...
Scalar functions can be used wherever an expression is valid. Categories of scalar functions Expand table Function categoryDescription Configuration Functions Return information about the current configuration. Conversion Functions Support data type casting and converting. Cursor Functions Return information ...
There is a range of NoSQL database types, but MongoDB stores data in JavaScript-like objects known asdocuments, whose content looks like this: {_id:"123", name:"Craig"} Although MongoDB has become synonymous with the JavaScript-based frameworkNode.js, official MongoDBdatabase driversare ava...
What Is SQL Server? SQL Server Definition Key Features of SQL Server SQL Server Data Types Common Use Cases and Applications SQL Server Performance Tuning and Monitoring SQL Server Definition Microsoft released SQL Server in 1989, building it on Structured Query Language (SQL). As a relational da...
of typing intricate sql commands, users can drag and drop fields or create links between records with just a few clicks. guis often layer upon one another to enhance functionality. for example, when you stream a video on a media player embedded in a website, you engage with multiple guis:...
.Net Framework Data Provider. It may not be installed. (MySQL) .NET pdf viewer .pdb files in production environment? 'An operation was attempted on a nonexistent network connection' error 'bootstrap' is not a valid script name. The name must end in '.js'. 'Cannot implicitly convert 'Sy...