Oracle select if null

Summary: in this tutorial, you will learn how to use the Oracle IS NULL and IS NOT NULL operators to check if a value in a column or an expression is NULL or not. Introduction to the Oracle IS NULL operator. In the database worl NULL is special. It is a marker for missing information or the information is not applicable.

Checking for NULL with Oracle SQL The art of doing mathematics consists in finding that special case which contains all the germs of generality. David Hilbert One of the most mindboggling values in the Oracle database is the NULL value. You cannot specify the literal NULL for expr1. If both arguments are numeric datatypes, then Oracle Database determines the argument with the higher numeric precedence, implicitly converts the other argument to that datatype, and returns that datatype. If the arguments are not numeric, then they must be of the same datatype, or Oracle returns.

If statement in select (ORACLE ) Ask Question Asked years, months ago. STREAM_NAME, since INSTR() returns NULL in that case. How to check if a select query result is NULL in. Select a column if other column is null. If exprand exprare equal, the NULLIF function returns NULL.

Otherwise, it returns expr1. For more information, see Using the NULL Statement. Description of the illustration null. By understanding the difference between IN, EXISTS, NOT IN, and NOT EXISTS, you can avoid a very common problem when NULLs appear in the data of a subquery.

Scott Stephens helps you understand. Tickets where DriverID = DriverTable. SQL Server , how do I verify if a query has returned NULL and run blocks depending on it. Is there a way in to just run a query once to select into a variable , considering that the query might return nothing, then in that case the variable should be null.

I can only run the query twice. The Oracle NULLIF() function accepts two arguments. It returns a null value if the two arguments are equal. In case the arguments are not equal, the NULLIF() function returns the first argument.

Let’s take a look at what NULLIF does and what you can use it for. Purpose of the Oracle NULLIF Function. If the two values match, the function will return NULL. In SQL Server, you can use ISNULL(exp exp2) function.

SELECT null , null INTO v_emp, v_age FROM employee WHERE rownum = 1;This is just plain silly. Say i have a table with 1columns of those is I i want to find the ID of rows whose other 1columns has not null Which one of below is better performance-wise? Why not simply have a where clause saying colis not null ? Connected to: Oracle Database 10g Enterprise Edition Release 10. This Oracle tutorial explains how to use the IF-THEN-ELSE statement in Oracle with syntax and examples. In Oracle , the IF-THEN-ELSE statement is used to execute code when a condition is TRUE, or execute different code if the condition evaluates to FALSE.

The simplest form of IF statement associates a Boolean expression with a sequence of statements enclosed by the keywords THEN and END IF. The sequence of statements is executed only if the expression returns TRUE. If the expression returns FALSE or NULL , the IF statement does nothing.

In either case, control passes to the next statement.