SQL Extensions

Grouped AVG Exact String

Grouped AVG skips NULLs and emits exact reduced strings.

highlighted = computed this step

Grouped AVG exact string

Grouped AVG skips NULL cells and emits an exact reduced string. The output is not a float and not a raw Fraction cell.

AVG skips NULL\text{AVG skips NULL}

Exact average token

The grouped output has 3 groups. The DB group uses 2 non-NULL scores and emits 80/1.

DB non NULL count=2,DB avg=80/1\text{DB non NULL count}=2,\quad \text{DB avg}=80/1

SQL extensions are rendered as tiny finite-table semantics; SQL dialect completeness, optimizer behavior, execution cost, full DDL behavior, and database-product claims are out of scope.

compiled summaryfactvaluerowCount3arity2rootKindgroup_avg Grouped AVGcourseavg_scoreDB80/1M10/1OS80/1 AVG non-NULL countsgroupnonNullCount[DB]2[M]1[OS]1

Summary

The exact AVG string is derived from integer cells after NULLs are skipped. Note: numeric types outside this toy surface are not modeled.

exact string average\text{exact string average}