Query semantics

A query is a JSON AST, not SQL. What it means is fixed by a set of rules, and each rule by conformance cases: one JSON file per case in crates/opengrid-conformance/cases/, each holding a query against the shared orders dataset and the exact expected answer.

{
  "id": "s8-decimal-is-exact",
  "rule": "S8",
  "query": {
    "source": "orders",
    "select": ["id", "amount"],
    "filter": { "field": "amount", "op": "eq", "value": "999999999.99" }
  },
  "expected": { "columns": ["id", "amount"], "rows": [[7, "999999999.99"]] },
  "ordered": false
}

Who answers them

The same case files run against

• the Arrow engine, natively (crates/opengrid-arrow-engine/tests/conformance_engine.rs),
• the WASM build in headless Chrome (crates/opengrid-wasm/tests/conformance_in_browser.rs),
• the hybrid path, with a source that refuses what it does not declare (crates/opengrid-arrow-engine/tests/conformance_hybrid.rs),
• PostgreSQL (crates/opengrid-datasource-postgres/tests/conformance_postgres.rs) — this one skips itself without a database; point it at one with OPENGRID_TEST_PG.

The rules, by their cases

Rule	What the cases pin
S1	Comparisons with NULL: eq and ne exclude NULL rows, NOT of an unknown stays unknown
S2	in lists, including the empty list, which matches nothing
S3	NULL ordering, ascending and descending
S4	Binary collation
S5	contains and starts_with are case-sensitive
S6	Multi-column sort and paging with offset
S7	NaN: not NULL, sorts after numbers, -0.0 equals 0.0
S8	Decimals are exact
S9	Dates have no time zone; timestamps keep microseconds
S10	NULL forms its own group, and the empty string is a different one
S11	Aggregates ignore NULL; count(*) versus count(field); empty sets
S12	Aggregate result types: sum of int64 stays int64, of decimal widens to 38 digits
S13	Unicode normalisation: NFC is not NFD
S14	The empty string is a value, not NULL
S15	Derived date-part columns (year, month) filter, sort and group like stored ones

The file names say the rest — s7-nan-sorts-after-numbers.json, s9-timestamp-microsecond-precision.json — and each file is short enough to read.