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DuckDB Extensions All extensions Apache DataSketches

REQ functions in the Apache DataSketches DuckDB extension

Function category

REQ

13 functions

[Relative-error quantile sketch](https://datasketches.apache.org/docs/REQ/ReqSketch.html). Error scales with rank rather than being fixed across the distribution — predictable accuracy on highly skewed data.

datasketch_req

Aggregate function REQ
Signature
datasketch_req(col0: INTEGER, col1: sketch_req_bigint | TINYINT | sketch_req_double | …) → <sketch>
Arguments (Positional)
Argument col0 Type INTEGER Mode Positional Description
Argument col1 Type sketch_req_bigint | TINYINT | sketch_req_double | …
20 concrete types
BIGINTDOUBLEFLOATINTEGERSMALLINTTINYINTUBIGINTUINTEGERUSMALLINTUTINYINTsketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Return type varies by input — 10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Description

Aggregate input values into a Relative Error Quantile sketch. Error scales with rank rather than being a fixed fraction of n — predictable accuracy on highly skewed distributions where a fixed-error sketch over- or under-spends precision at the extremes.

1 Example 1 
SELECT datasketch_req(k, data);
Related functions

datasketch_req_cdf

Scalar function REQ
Signature
datasketch_req_cdf( col0: <sketch>, col1: <numeric>[], col2: BOOLEAN ) → <numeric>[]
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Argument col1 Type <numeric>[]
10 concrete types
BIGINT[]DOUBLE[]FLOAT[]INTEGER[]SMALLINT[]TINYINT[]UBIGINT[]UINTEGER[]USMALLINT[]UTINYINT[]
Mode Positional Description
Argument col2 Type BOOLEAN Mode Positional Description
Return type varies by input — 10 concrete types
BIGINT[]DOUBLE[]FLOAT[]INTEGER[]SMALLINT[]TINYINT[]UBIGINT[]UINTEGER[]USMALLINT[]UTINYINT[]
Description

Return the Cumulative Distribution Function (CDF) of the sketch for a series of points

1 Example 1 
SELECT datasketch_req_cdf(sketch, points, inclusive);
Related functions

datasketch_req_describe

Scalar function REQ
Signature
datasketch_req_describe( col0: <sketch>, col1: BOOLEAN, col2: BOOLEAN ) → VARCHAR
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Argument col1 Type BOOLEAN Mode Positional Description
Argument col2 Type BOOLEAN Mode Positional Description
Description

Return a description of this sketch

1 Example 1 
SELECT datasketch_req_describe(sketch, include_levels, include_items);
Related functions

datasketch_req_is_empty

Scalar function REQ
Signature
datasketch_req_is_empty(col0: <sketch>) → BOOLEAN
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Description

Return a boolean indicating if the sketch is empty

1 Example 1 
SELECT datasketch_req_is_empty(sketch);
Related functions

datasketch_req_is_estimation_mode

Scalar function REQ
Signature
datasketch_req_is_estimation_mode(col0: <sketch>) → BOOLEAN
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Description

Return a boolean indicating if the sketch is in estimation mode

1 Example 1 
SELECT datasketch_req_is_estimation_mode(sketch);
Related functions

datasketch_req_k

Scalar function REQ
Signature
datasketch_req_k(col0: <sketch>) → USMALLINT
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Description

Return the value of K for this sketch

1 Example 1 
SELECT datasketch_req_k(sketch);
Related functions

datasketch_req_max_item

Scalar function REQ
Signature
datasketch_req_max_item(col0: <sketch>) → <numeric>
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Return type varies by input — 10 concrete types
BIGINTDOUBLEFLOATINTEGERSMALLINTTINYINTUBIGINTUINTEGERUSMALLINTUTINYINT
Description

Return the maxium item in the sketch

1 Example 1 
SELECT datasketch_req_max_item(sketch);
Related functions

datasketch_req_min_item

Scalar function REQ
Signature
datasketch_req_min_item(col0: <sketch>) → <numeric>
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Return type varies by input — 10 concrete types
BIGINTDOUBLEFLOATINTEGERSMALLINTTINYINTUBIGINTUINTEGERUSMALLINTUTINYINT
Description

Return the minimum item in the sketch

1 Example 1 
SELECT datasketch_req_min_item(sketch);
Related functions

datasketch_req_n

Scalar function REQ
Signature
datasketch_req_n(col0: <sketch>) → UBIGINT
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Description

Return the number of items contained in the sketch

1 Example 1 
SELECT datasketch_req_rank(sketch);
Related functions

datasketch_req_num_retained

Scalar function REQ
Signature
datasketch_req_num_retained(col0: <sketch>) → UBIGINT
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Description

Return the number of retained items in the sketch

1 Example 1 
SELECT datasketch_req_num_retained(sketch);
Related functions

datasketch_req_pmf

Scalar function REQ
Signature
datasketch_req_pmf( col0: <sketch>, col1: <numeric>[], col2: BOOLEAN ) → <numeric>[]
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Argument col1 Type <numeric>[]
10 concrete types
BIGINT[]DOUBLE[]FLOAT[]INTEGER[]SMALLINT[]TINYINT[]UBIGINT[]UINTEGER[]USMALLINT[]UTINYINT[]
Mode Positional Description
Argument col2 Type BOOLEAN Mode Positional Description
Return type varies by input — 10 concrete types
BIGINT[]DOUBLE[]FLOAT[]INTEGER[]SMALLINT[]TINYINT[]UBIGINT[]UINTEGER[]USMALLINT[]UTINYINT[]
Description

Return the Probability Mass Function (PMF) of the sketch for a series of points

1 Example 1 
SELECT datasketch_req_pmf(sketch, points, inclusive);
Related functions

datasketch_req_quantile

Scalar function REQ
Signature
datasketch_req_quantile( col0: <sketch>, col1: DOUBLE, col2: BOOLEAN ) → <numeric>
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Argument col1 Type DOUBLE Mode Positional Description
Argument col2 Type BOOLEAN Mode Positional Description
Return type varies by input — 10 concrete types
BIGINTDOUBLEFLOATINTEGERSMALLINTTINYINTUBIGINTUINTEGERUSMALLINTUTINYINT
Description

Approximate quantile at a given rank from a REQ sketch.

1 Example 1 
SELECT datasketch_req_rank(sketch, rank, inclusive);
Related functions

datasketch_req_rank

Scalar function REQ
Signature
datasketch_req_rank( col0: <sketch>, col1: <numeric>, col2: BOOLEAN ) → DOUBLE
Arguments (Positional)
Argument col0 Type <sketch>
10 concrete types
sketch_req_bigintsketch_req_doublesketch_req_floatsketch_req_integersketch_req_smallintsketch_req_tinyintsketch_req_ubigintsketch_req_uintegersketch_req_usmallintsketch_req_utinyint
Mode Positional Description
Argument col1 Type <numeric>
10 concrete types
BIGINTDOUBLEFLOATINTEGERSMALLINTTINYINTUBIGINTUINTEGERUSMALLINTUTINYINT
Mode Positional Description
Argument col2 Type BOOLEAN Mode Positional Description
Description

Approximate rank of a value within the REQ sketch.

1 Example 1 
SELECT datasketch_req_rank(sketch, item, inclusive);
Related functions