SQL SSIS syntax question

Question

What do you call the following expression?

(TableName == NULL) ? "0" : TableName

I have a sense of what it does, but would like to look up the whole syntax definition, however as there is no real descriptor in the expression I can't seem to find out what it's called.

Answer 1

It's what is known in programming as a Ternary Operator. It's common in C/C++, JavaScript and PHP (among other languages).

As tombom states, the idea is that it is a short-hand if statement:

<condition> ? <true-case-code> : <false-case-code>;

SQL Server 2012 and above has it's own Ternary Operator in the form of the IIF statement.

IIF(@type = 2, 1, 0)

• Reaces: Marking this one as correct because it has a linked reference, and is the first answer that contains the actual name.

Answer 2

This is short for

<if> ? <then> : <else>

at least in programming that is, like in C++ and so on.

Answer 3

This type of expression is called a Ternary operator. Its standard form is

condition ? value_if_true : value_if_false

Using your example of

(TableName == NULL) ? "0": TableName

if TableName == NULL then "0" is returned

if TableName !==Null then TableName is returned

You could rewrite the ternary expression as

if(TableName==NULL) then "0" else TableName

but this is more verbose than the original Ternary expression.