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115 lines
4.0 KiB
Markdown
115 lines
4.0 KiB
Markdown
---
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slug: /en/sql-reference/aggregate-functions/reference/argmin
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sidebar_position: 105
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---
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# argMin
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Calculates the `arg` value for a minimum `val` value. If there are several different values of `arg` for minimum values of `val`, returns the first of these values encountered.
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Both parts the `arg` and the `min` behave as [aggregate functions](/docs/en/sql-reference/aggregate-functions/index.md), they both [skip `Null`](/docs/en/sql-reference/aggregate-functions/index.md#null-processing) during processing and return not `Null` values if not `Null` values are available.
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**Syntax**
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``` sql
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argMin(arg, val)
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```
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**Arguments**
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- `arg` — Argument.
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- `val` — Value.
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**Returned value**
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- `arg` value that corresponds to minimum `val` value.
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Type: matches `arg` type.
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**Example**
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Input table:
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``` text
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┌─user─────┬─salary─┐
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│ director │ 5000 │
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│ manager │ 3000 │
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│ worker │ 1000 │
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└──────────┴────────┘
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```
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Query:
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``` sql
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SELECT argMin(user, salary) FROM salary
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```
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Result:
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``` text
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┌─argMin(user, salary)─┐
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│ worker │
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└──────────────────────┘
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```
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**Extended example**
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```sql
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CREATE TABLE test
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(
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a Nullable(String),
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b Nullable(Int64)
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)
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ENGINE = Memory AS
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SELECT *
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FROM VALUES((NULL, 0), ('a', 1), ('b', 2), ('c', 2), (NULL, NULL), ('d', NULL));
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select * from test;
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┌─a────┬────b─┐
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│ ᴺᵁᴸᴸ │ 0 │
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│ a │ 1 │
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│ b │ 2 │
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│ c │ 2 │
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│ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │
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│ d │ ᴺᵁᴸᴸ │
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└──────┴──────┘
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SELECT argMin(a, b), min(b) FROM test;
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┌─argMin(a, b)─┬─min(b)─┐
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│ a │ 0 │ -- argMin = a because it the first not `NULL` value, min(b) is from another row!
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└──────────────┴────────┘
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SELECT argMin(tuple(a), b) FROM test;
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┌─argMin(tuple(a), b)─┐
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│ (NULL) │ -- The a `Tuple` that contains only a `NULL` value is not `NULL`, so the aggregate functions won't skip that row because of that `NULL` value
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└─────────────────────┘
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SELECT (argMin((a, b), b) as t).1 argMinA, t.2 argMinB from test;
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┌─argMinA─┬─argMinB─┐
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│ ᴺᵁᴸᴸ │ 0 │ -- you can use `Tuple` and get both (all - tuple(*)) columns for the according max(b)
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└─────────┴─────────┘
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SELECT argMin(a, b), min(b) FROM test WHERE a IS NULL and b IS NULL;
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┌─argMin(a, b)─┬─min(b)─┐
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│ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ -- All aggregated rows contains at least one `NULL` value because of the filter, so all rows are skipped, therefore the result will be `NULL`
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└──────────────┴────────┘
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SELECT argMin(a, (b, a)), min(tuple(b, a)) FROM test;
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┌─argMin(a, tuple(b, a))─┬─min(tuple(b, a))─┐
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│ d │ (NULL,NULL) │ -- 'd' is the first not `NULL` value for the min
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└────────────────────────┴──────────────────┘
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SELECT argMin((a, b), (b, a)), min(tuple(b, a)) FROM test;
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┌─argMin(tuple(a, b), tuple(b, a))─┬─min(tuple(b, a))─┐
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│ (NULL,NULL) │ (NULL,NULL) │ -- argMin returns (NULL,NULL) here because `Tuple` allows to don't skip `NULL` and min(tuple(b, a)) in this case is minimal value for this dataset
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└──────────────────────────────────┴──────────────────┘
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SELECT argMin(a, tuple(b)) FROM test;
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┌─argMin(a, tuple(b))─┐
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│ d │ -- `Tuple` can be used in `min` to not skip rows with `NULL` values as b.
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└─────────────────────┘
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```
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**See also**
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- [Tuple](/docs/en/sql-reference/data-types/tuple.md)
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