@terascope/data-mate / function-configs/numeric/sql-utils

function-configs/numeric/sql-utils

Variables

FRACTIONAL_FIELD_TYPES

const FRACTIONAL_FIELD_TYPES: readonly string[]

Defined in: data-mate/src/function-configs/numeric/sql-utils.ts:44

The numeric field types setPrecision handles in SQL: the ones that can hold a fraction.

validateAccepts treats [Number] as every numeric width, so types cannot exclude the integer types and applies checks this list instead.

Functions

foldList()

foldList(value, operator): string

Defined in: data-mate/src/function-configs/numeric/sql-utils.ts:32

A left fold over the non-null elements, or NULL when there are none.

The empty check is required: list_reduce raises an error on an empty list, while the JavaScript reducer returns null.

Uses lambda a, b : ... because the (a, b) -> ... form is disabled by default in DuckDB v2.0 and removed in v2.1.

Parameters

Parameter	Type
value	string
operator	string

Returns

string

---

isArrayColumn()

isArrayColumn(_args, inputConfig?): boolean

Defined in: data-mate/src/function-configs/numeric/sql-utils.ts:14

True when the column is an array, the only shape the *Values reducers fold.

On a scalar column these functions return the value unchanged, and list_sum of a scalar is not valid SQL, so scalar columns keep the UDF.

Parameters

Parameter	Type
_args	unknown
inputConfig?	DataTypeFieldAndChildren

Returns

boolean

---

notAtRoundingTie()

notAtRoundingTie(value, digits): string

Defined in: data-mate/src/function-configs/numeric/sql-utils.ts:67

True when printf at digits is guaranteed to agree with toFixed - see toFixedSql.

Parameters

Parameter	Type
value	string
digits	number

Returns

string

---

toFixedSql()

toFixedSql(value, digits): string

Defined in: data-mate/src/function-configs/numeric/sql-utils.ts:62

parseFloat(value.toFixed(digits)) in SQL.

toFixed rounds the value's exact binary expansion, so (2.675).toFixed(2) is '2.67' (the stored value is 2.67499999...). DuckDB's round(2.675, 2) and a DECIMAL cast both give 2.68. printf('%.{d}f', v) also rounds the exact value and agrees with toFixed except at exact ties, where printf rounds half to even and toFixed rounds half away from zero (%.0f of 2.5 is 2, toFixed(0) is '3').

notAtRoundingTie excludes those ties. A tie means the exact value ends with a 5 at digit d + 1, so if the rendering at d + 1 digits does not end in 5 it is not a tie and the two roundings agree. Non-finite values also keep the UDF, because setPrecision returns them unchanged and printf renders them as nan/inf.

Parameters

Parameter	Type
value	string
digits	number

Returns

string

---

truncateToDigitsSql()

truncateToDigitsSql(value, digits): string

Defined in: data-mate/src/function-configs/numeric/sql-utils.ts:78

truncateNumber in SQL: render at digits + 5 decimals, then keep the first digits.

trunc(v * 10^d) / 10^d would be wrong: 8.29 * 100 is 828.99999999999989, so it gives 8.28 where truncateNumber gives 8.29. The digits + 5 rendering can itself round up at a tie and change the kept digits, so callers apply the same notAtRoundingTie guard.

Parameters

Parameter	Type
value	string
digits	number

Returns

string