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82 lines
1.8 KiB
Markdown
82 lines
1.8 KiB
Markdown
---
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slug: /en/sql-reference/aggregate-functions/reference/last_value
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sidebar_position: 160
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---
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# last_value
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Selects the last encountered value, similar to `anyLast`, but could accept NULL.
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Mostly it should be used with [Window Functions](../../window-functions/index.md).
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Without Window Functions the result will be random if the source stream is not ordered.
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## examples
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```sql
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CREATE TABLE test_data
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(
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a Int64,
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b Nullable(Int64)
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)
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ENGINE = Memory;
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INSERT INTO test_data (a, b) Values (1,null), (2,3), (4, 5), (6,null)
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```
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### example1
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The NULL value is ignored at default.
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```sql
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select last_value(b) from test_data
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```
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```text
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┌─last_value_ignore_nulls(b)─┐
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│ 5 │
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└────────────────────────────┘
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```
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### example2
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The NULL value is ignored.
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```sql
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select last_value(b) ignore nulls from test_data
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```
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```text
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┌─last_value_ignore_nulls(b)─┐
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│ 5 │
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└────────────────────────────┘
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```
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### example3
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The NULL value is accepted.
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```sql
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select last_value(b) respect nulls from test_data
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```
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```text
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┌─last_value_respect_nulls(b)─┐
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│ ᴺᵁᴸᴸ │
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└─────────────────────────────┘
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```
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### example4
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Stabilized result using the sub-query with `ORDER BY`.
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```sql
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SELECT
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last_value_respect_nulls(b),
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last_value(b)
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FROM
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(
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SELECT *
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FROM test_data
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ORDER BY a ASC
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)
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```
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```text
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┌─last_value_respect_nulls(b)─┬─last_value(b)─┐
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│ ᴺᵁᴸᴸ │ 5 │
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└─────────────────────────────┴───────────────┘
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```
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