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Can I use CASE statement in where clause?

Can I use CASE statement in where clause?

CASE STATEMENT IN WHERE CLAUSE: The CASE statement returns the value based on condition. We can use a case statement in Where, Order by and Group by clause.

Can I use CASE statement in where clause in Oracle?

Oracle CASE expression allows you to add if-else logic to SQL statements without having to call a procedure. For example, you can use the CASE expression in statements such as SELECT , UPDATE , or DELETE , and in clauses like SELECT , WHERE , HAVING , and ORDDER BY .

How do you check for null in a case statement?

You cannot use simple case to test for null because it always uses the equals operator ( = ). That is because the condition null = null is not true5—consequently, a when null clause never applies. If the is null , the else clause applies.

Can we use select statement inside case statement Oracle?

With CASE expression, the above multiple statements on the same table can be avoided using Oracle select case. from emp; E.g.: CASE expression can also be nested. E.g.: The data types of the returned values should be the same.

Can we use CASE statement in update query?

You must include at least one WHEN clause within the CASE expression; subsequent WHEN clauses and the ELSE clause are optional. If no WHEN condition evaluates to true, the resulting value is null.

Can we use subquery in case statement?

Case Statement and Subquery Example This example use the Subquery inside a Case Statement in SQL Server. First, the Subquery will execute and finds the Average of the Sales amount. Same as IF ELSE statement.

Can you put a SELECT statement in a case statement?

The CASE expression is a conditional expression: it evaluates data and returns a result. The result it returns is based on whether the data meets certain criteria. This expression can be used in SELECT , UPDATE , and DELETE statements or in WHERE , IN , LIKE , ORDER BY , and HAVING clauses.

When does the where clause for IS NULL return 0?

Same happend is you pass 0 for @ActiveEmployees and there is a row where the value of column [TerminatedDate] is null, in this case the case function will return 0, because the employee is active and you want non active ones. Searchable? SQL Server will not be able to use statistics to estimate cardinality.

How to write case when in where statement in Oracle?

In MySQL it executes ok, but in Oracle it fails with error: How should I write this SQL? You’re mixing up two ways of doing case. You either need: CASE WHEN THEN … CASE WHEN THEN

Which is the same as null in Oracle SQL?

And then here’s the table with data: Thanks in advance. Never forget that in Oracle SQL the ” literal (empty string) is the same as NULL, hence your predicate e.ColumnName != ” is equivalent to e.ColumnName != null which always evaluates to NULL. Second problem is that you are trying output a boolean value from your CASE.

How to use clause stack overflow in Oracle?

SELECT Employee.EmployeeId, Employee.EmployeeName, Employee.Description, Employee.IsFrozen FROM employee, employeerole, roledef WHERE employee.employeeid = employeerole.employeeid AND employeerole.roleid = roledef.roleid AND rolename IN ( CASE WHEN (1 < 2) THEN (‘Owner Role’) WHEN (2 < 1) THEN (‘Eval Owner Role’) END);