Categories:: Conditional expression functions

GREATEST_IGNORE_NULLS¶

Returns the largest non-NULL value from a list of expressions. GREATEST_IGNORE_NULLS supports all data types, including VARIANT.

See also:: GREATEST

Syntax¶

GREATEST_IGNORE_NULLS( <expr1> [ , <expr2> ... ] )

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Arguments¶

exprN: The arguments must include at least one expression. All the expressions should be of the same type or compatible types.

Returns¶

The first argument determines the return type:

If the first type is numeric, then the return type is ‘widened’ according to the numeric types in the list of all arguments.
If the first type is not numeric, then all other arguments must be convertible to the first type.

If all arguments are NULL, returns NULL.

Collation details¶

The collation specifications of all input arguments must be compatible.
The comparisons follow the collation based on the input arguments’ collations and precedences.
The collation of the result of the function is the highest-precedence collation of the inputs.

Examples¶

Create a table and insert some values:

CREATE TABLE test_greatest_ignore_nulls (
  col_1 INTEGER,
  col_2 INTEGER,
  col_3 INTEGER,
  col_4 FLOAT);

INSERT INTO test_greatest_ignore_nulls (col_1, col_2, col_3, col_4) VALUES
  (1, 2,    3,  4.25),
  (2, 4,   -1,  NULL),
  (3, 6, NULL,  -2.75);

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Run a SELECT statement that returns the greatest non-null value in each row of the table:

SELECT col_1,
       col_2,
       col_3,
       col_4,
       GREATEST_IGNORE_NULLS(col_1, col_2, col_3, col_4) AS greatest_ignore_nulls
 FROM test_greatest_ignore_nulls
 ORDER BY col_1;

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+-------+-------+-------+-------+-----------------------+
| COL_1 | COL_2 | COL_3 | COL_4 | GREATEST_IGNORE_NULLS |
|-------+-------+-------+-------+-----------------------|
|     1 |     2 |     3 |  4.25 |                  4.25 |
|     2 |     4 |    -1 |  NULL |                  4    |
|     3 |     6 |  NULL | -2.75 |                  6    |
+-------+-------+-------+-------+-----------------------+