plsql - Oracle PL/SQL 可以将整数评估为布尔值吗？

Answer 1

First off, what you are talking about does not appear to have anything to do with short-circuit evaluation. Short-circuit evaluation would be when code like

IF( quick_condition AND slow_condition )
THEN
  <<do something>>
END IF;

evaluates the second slow condition if and only if the initial quick condition evaluates to TRUE.

Second, your assignment of a value to v_ssn_ind is not syntactically valid.

Third, no, you cannot say

IF <<integer variable>>
THEN

because that would not make sense. What value would evaluate to TRUE and what value would evaluate to FALSE? If 0 is FALSE and 1 is TRUE, for example, what would 17 translate to?

If you are declaring some sort of indicator variable, it would generally make sense to use a BOOLEAN data type rather than an integer. If you use a boolean, then you can do

IF <<boolean variable>>
THEN

because that eliminates the ambiguity. This won't be any faster than adding the = TRUE to your IF condition however.

Answer 2

I discourage you from putting any logic into a declaration block, in my opinion it makes code less clear.

Instead IF you can use CASE statement.

...
    v_ssn_ind INTEGER;
BEGIN
    v_ssn_ind := CASE TRIM(p_ssn) IS NULL WHEN TRUE THEN 0 ELSE 1 END;
...

But personally I would chose BOOLEAN type for v_ssn_ind

...
    v_ssn_ind BOOLEAN;
BEGIN
    v_ssn_ind := TRIM(p_ssn) IS NOT NULL;
...