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create table test (column1 int, column2 int, column3 int);
insert into test values (1,2,3);
insert into test values (1,NULL,NULL);
insert into test values (NULL,4,5);
insert into test values (NULL,NULL,6);
insert into test values (0,0,0);
insert into test values(NULL,NULL,NULL);
SELECT column1, column2, column3,
column1 + column2 + column3 AS sum,
COALESCE(column1,0) + COALESCE(column2,0) + COALESCE(column3,0) AS sum2,
COALESCE(column1,column2,column3,100) AS value FROM test;
| column1 | column2 | column3 | sum | sum2 | value |
|---|---|---|---|---|---|
| 1 | 2 | 3 | 6 | 6 | 1 |
| 1 | null | null | null | 1 | 1 |
| null | 4 | 5 | null | 9 | 4 |
| null | null | 6 | null | 6 | 6 |
| 0 | 0 | 0 | 0 | 0 | 0 |
| null | null | null | null | 0 | 100 |
SELECT CASE WHEN column1 IS NULL THEN 0 ELSE column1 END AS column1,
COALESCE(column1,0) AS column1_b FROM test;
| column1 | column1_b |
|---|---|
| 1 | 1 |
| 1 | 1 |
| 0 | 0 |
| 0 | 0 |
| 0 | 0 |
| 0 | 0 |