How to select make the default value of all my variables '0' when only nulls are being returned? - sql

Question

So I am running into issues where my conditional statements don't work because I am doing comparisons (at times for certain situations) where I'm comparing a null with an integer. I tried using an exception but after printing the variable values onto my display i found out that this exception only handled 'NO_DATA_FOUND' error messages. Is there a way I can get the variable to get a '0' selected into it in the case a 'NULL' or BLANK is returned? Below is my code:
SELECT MAX(VALUE)
INTO VARIABLE_1
FROM VALUE V
JOIN REL_VALUE RV on V.value_id = RV.value_id
WHERE CODE = rCode
AND FIELD_TX = 'HI';
SELECT MAX(VALUE)
INTO VARIABLE_2
FROM VALUE V
JOIN REL_VALUE RV on V.value_id = RV.value_id
WHERE CODE = rCode
AND FIELD_TX = 'BYE';
---
EXCEPTION
WHEN no_data_found
THEN SELECT 0
INTO VARIABLE_1
FROM DUAL;
SELECT 0
INTO VARIABLE_2
FROM DUAL;

Answer 1

You can use nvl() to provide a default value:
SELECT NVL(MAX(VALUE), 0)
INTO VARIABLE_1
FROM VALUE V
JOIN REL_VALUE RV on V.value_id = RV.value_id
WHERE CODE = rCode
AND FIELD_TX = 'HI';
SELECT NVL(MAX(VALUE), 0)
INTO VARIABLE_2
FROM VALUE V
JOIN REL_VALUE RV on V.value_id = RV.value_id
WHERE CODE = rCode
AND FIELD_TX = 'BYE';
The no_data_found exception won't be raised because you're using an aggregate function; that will always return one row, even its value is null. A null value is not the same as no rows being returned.

Answer 2

Or you can use coalesce
SELECT coalesce(MAX(VALUE), 0) AS value
INTO VARIABLE_1
FROM VALUE V
JOIN REL_VALUE RV on V.value_id = RV.value_id
WHERE CODE = rCode
AND FIELD_TX = 'HI';
SELECT coalesce(MAX(VALUE), 0) AS value
INTO VARIABLE_2
FROM VALUE V
JOIN REL_VALUE RV on V.value_id = RV.value_id
WHERE CODE = rCode
AND FIELD_TX = 'BYE';

Answer 3

use nvl command for it like :
nvl(column_name,0).