Explanation: The UPDATE statement updates the status of employees with IDs 2,4, and 5 to INACTIVE. Difference Between Updating Multiple Records with and Without CASE WHEN Parameter With CASE WHEN Without CASE WHEN Use Case It can be used when different rows have to be updated with different va...
Because we defined the Staff column in the subquery, we can refer to it in the outer query. This makes re-using code much easier and it makes the SQL statement more compact and easier to maintain. If we would like to change the definition of Staff, we would need to alter it at only...
subquery-related keywords比如IN,ANY,SOME,EXISTS仅仅返回true或者false,而这非常适合使用where clause subquery 你也可以在UPDATE, DELETE STATEMENTS中的where clause中使用corelated subquery以便narrow down哪些row将可以被这条statement所影响。 下面的correlated query执行过程: selectdistincta.ProductID, a.UnitPriceas...
14.2.9.3 UNION Syntax 14.2.10 Subquery Syntax s A subquery is aSELECTstatement within another statement. 14.2.10.1 The Subquery as Scalar Operand note:For the subquery just shown, ift1were empty, the result would beNULLeven thoughs2isNOT NULL. 14.2.10.2 Comparisons Using Subqueries 14.2.11 UP...
The SQL subquery is a SELECT query that is embedded in the main SELECT statement. The subquery can be nested inside a SELECT, INSERT, UPDATE, or DELETE statement or inside another subquery.
One thing I learned early on when I was getting to know SQL macros is that we cannot replace each and every part of a SQL statement with a macro. In the same way, working with table SQL macros, we cannot represent just any part of the result string by referencing parameters inside it...
4.3. CASE Statements and Subqueries We can couple CASE statements withsubqueriesto create even more dynamic queries. For example, let’s say we want to assign a rank to each student based on their GPA within their respective departments. We can use a CASE statement along with a subquery to ...
You cannot use the TO_LOB function to convert a LONG column to a LOB column in the subquery of a CREATE TABLE ...AS SELECT statement if you are creating an index-organized table. Instead, create the index-organized table without the LONG column, and then use the TO_LOB function in an...
In SQL, the SELECT INTO statement is used to copy data from one table to another. In this tutorial, you will learn about the SQL SELECT INTO statement with the help of examples.
The innerSELECTstatement retrieves the IDs of departments with location ID 1800. These department IDs are needed by the outer query block, which retrieves names of employees in the departments whose IDs were supplied by the subquery. The structure of the SQL statement does not force the databas...