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IS [ NOT ] NULL¶
Determines whether an expression is NULL or is not NULL.
Syntax¶
<expr> IS [ NOT ] NULL
Returns¶
Returns a BOOLEAN.
When IS NULL is specified, the value is TRUE if the expression is NULL. Otherwise, returns FALSE.
When IS NOT NULL is specified, the value is TRUE if the expression is not NULL. Otherwise, returns FALSE.
Examples¶
Create the test_is_not_null
table and load the data:
CREATE OR REPLACE TABLE test_is_not_null (id NUMBER, col1 NUMBER, col2 NUMBER);
INSERT INTO test_is_not_null (id, col1, col2) VALUES
(1, 0, 5),
(2, 0, NULL),
(3, NULL, 5),
(4, NULL, NULL);
Show the data in the test_is_not_null
table:
SELECT *
FROM test_is_not_null
ORDER BY id;
+----+------+------+
| ID | COL1 | COL2 |
|----+------+------|
| 1 | 0 | 5 |
| 2 | 0 | NULL |
| 3 | NULL | 5 |
| 4 | NULL | NULL |
+----+------+------+
Use IS NOT NULL to return the rows for which the values in col1
are not NULL:
SELECT *
FROM test_is_not_null
WHERE col1 IS NOT NULL
ORDER BY id;
+----+------+------+
| ID | COL1 | COL2 |
|----+------+------|
| 1 | 0 | 5 |
| 2 | 0 | NULL |
+----+------+------+
Use IS NULL to return the rows for which the values in col2
are NULL:
SELECT *
FROM test_is_not_null
WHERE col2 IS NULL
ORDER BY id;
+----+------+------+
| ID | COL1 | COL2 |
|----+------+------|
| 2 | 0 | NULL |
| 4 | NULL | NULL |
+----+------+------+
Use a combination of IS NOT NULL and IS NULL to return the rows for which either of the following conditions is met:
The values in
col1
are not NULL.The values in
col2
are NULL.
SELECT *
FROM test_is_not_null
WHERE col1 IS NOT NULL OR col2 IS NULL
ORDER BY id;
+----+------+------+
| ID | COL1 | COL2 |
|----+------+------|
| 1 | 0 | 5 |
| 2 | 0 | NULL |
| 4 | NULL | NULL |
+----+------+------+
Use a combination of IS NOT NULL and IS NULL to return the rows for which both of the following conditions are met:
The values in
col1
are not NULL.The values in
col2
are NULL.
SELECT *
FROM test_is_not_null
WHERE col1 IS NOT NULL AND col2 IS NULL
ORDER BY id;
+----+------+------+
| ID | COL1 | COL2 |
|----+------+------|
| 2 | 0 | NULL |
+----+------+------+