statementUsing MSSQL Case Statements for Conditional Queries（mssqlcase）

Writing conditional queries among different databases is a challenging task for developers. Fortunately, the MSSQL Case statement makes it easy and efficient to write queries in such contexts.

The MSSQL Case statement is a helpful tool for transforming data between different databases and formats. In MSSQL, the case statement allows a developer to test a condition or multiple conditions, in order for queries to return different results. The statement is usually used in the SELECT clause when outputting a result set from a query. It’s possible to construct the CASE statement with multiple conditions and multiple outcomes.

For example, let’s say we have a table called Employees which expresses the monthly salary of employees. We want to update the employees’ salary according to specific conditions. With the CASE statement, we can easily solve this problem.

Here is the query written in MSSQL:

`UPDATE Employees

SET Salary =

CASE

WHEN ExistingSalary

WHEN ExistingSalary > 2000 AND ExistingSalary

ELSE ExistingSalary*1.01

END

WHERE ExistingSalary >= 2000;`

The query above will update the salary of every employee with an existing salary of more than or equal to $ 2000 with a bonus or a salary increase.

The CASE statement is also a good choice when dealing with NULL values. For instance, the query below will list all the employees whose designation is “Manager”, “Developer”, or “Tester”, or “NULL” if their job title is unspecified.

`SELECT

name,

designation

CASE

WHEN designation IS NULL THEN NULL

WHEN designation = ‘Manager’ THEN ‘MGR’

WHEN designation = ‘Developer’ THEN ‘DEV’

WHEN designation = ‘Tester’ THEN ‘TEST’

END AS ‘Designation Abbr’

FROM Employees`

So, by using the MSSQL Case statement, developers can create conditional queries efficiently and conveniently. This is particularly useful in comparison to heavy IF-ELSE statements which require extra coding. Moreover, the Case statement helps cut down the size of query code significantly, which in turn increases the performance and readability of the query.

To conclude, the MSSQL Case statement is a valuable asset for developers who need to transform data between databases and different formats. It is an efficient and effective tool to write high performance queries with less code.