fix(mysql): apply unique table alias on self-referential relationship subqueries#97
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… subqueries When a relationship's source and target are the same collection (e.g. regions.parentRegionId → regions.id), the correlated subquery was aliased with the same name as the outer table scan. MySQL resolved both sides of the JOIN condition to the inner scope, turning: WHERE regions.parentRegionId = regions.id …into a tautological self-comparison that always returned no rows, with no error surfaced in GraphQL or connector logs. Fix: derive a unique inner alias from the field alias and target collection name (e.g. "parentRegion_regions") and pass it through to: - the FROM clause alias (FROM regions AS parentRegion_regions) - mkJoinWhereClause (WHERE regions.FK = parentRegion_regions.PK) - getSelectOrderFields / getConcatOrderFields / translateIROrderByField - expressionToCondition (predicate field references inside the subquery) - collectRequiredJoinTablesForWhereClause rootTable arg - the derived-table alias passed to asTable() Cross-table relationships are unaffected: the inner alias always differs from the outer table name, and existing behaviour for non-self-joins is preserved by the defaulted innerAlias parameter on mkJoinWhereClause. Adds a query-request fixture for the self-referential object relationship case (regions → parentRegion via parentRegionId → id). Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This was referenced May 5, 2026
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Bumps the MySQL connector to **v1.0.19**. > Re-opened from #742 on an upstream branch — fork PRs fail CI because GitHub Actions strips repo/org secrets from `pull_request` runs originating in forks. ## Changes Picks up [hasura/ndc-jvm-mono#97](hasura/ndc-jvm-mono#97) — *fix(mysql): apply unique table alias on self-referential relationship subqueries*. When a relationship's source and target are the same collection (e.g. `regions.parentRegionId → regions.id`), the correlated subquery was previously aliased with the same name as the outer table scan. MySQL resolved both sides of the join condition to the inner scope, producing a tautological self-comparison that silently returned no rows. Equivalent fix to [#88](hasura/ndc-jvm-mono#88) (Snowflake/Trino) applied to MySQL's `JSONGenerator.kt`. ## Release artifacts - Tag: [`mysql/v1.0.19`](https://github.com/hasura/ndc-jvm-mono/releases/tag/mysql/v1.0.19) - Image: `ghcr.io/hasura/ndc-jvm-mysql:v1.0.19` (linux/amd64, linux/arm64) - CLI: `ghcr.io/hasura/ndc-jvm-cli:v1.0.19-mysql` - Source commit: `631d37452f26c736ed073c04bdce37d55bbff814` - Tarball sha256: `abfaf09c97327fe5d6bd1e98ba4df2c6d6fd5577c5f60d8b00d3ee10f8b28af0` Original contributor: @qamar-hashmi. Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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…predicates PR hasura#97 (v1.0.19) introduced a unique inner alias for self-referential subqueries to fix self-join correlation. The alias was threaded through expressionToCondition via the existing 3-arg overload, which does request.copy(collection = alias). That single field on QueryRequest is consumed for two distinct purposes downstream: 1. SQL table qualification of empty-path columns (correct: must use alias) 2. Connector-config lookup in BaseGenerator.getColumnType (incorrect: must use the real collection name) When a relationship's WHERE filter referenced a column on the aliased subquery table, getColumnType received the alias and threw: IllegalStateException: Collection products_products not found in connector configuration This affected nested cross-table relationships with WHERE filters as well as the intended self-join + WHERE case. Fix: introduce expressionToConditionWithSqlAlias on BaseGenerator. It accepts a QueryRequest whose .collection is the real collection name (used for config lookup) plus a separate sqlTableAlias used only for SQL table qualification of empty-path columns. The alias propagates through And/Or/Not recursion and into the outer-table qualifier of EXISTS join conditions, but is reset to null inside the EXISTS predicate (which switches collection context). Existing 2-arg and 3-arg expressionToCondition overloads are preserved for callers that want a fully real-collection context. JSONGenerator.kt swaps the buggy expressionToCondition(predicate, request, effectiveAlias) for expressionToConditionWithSqlAlias(predicate, request, effectiveAlias). request.collection now stays as the real collection name. Adds unit tests in ndc-sqlgen covering: empty-path predicate qualifies SQL with alias while config lookup uses the real collection, default 2-arg behaviour is unchanged, the regression no longer throws, alias propagates through compound predicates. Tests load a fixture configuration.json via HASURA_CONFIGURATION_DIRECTORY set on the Gradle test task. Adds JSON query-request fixtures for the four reported regression scenarios: self-join with WHERE, single-level cross-table with WHERE, nested cross-table with WHERE (the original bug report), and deep mixed self-join + cross-table with WHERE. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
This was referenced May 7, 2026
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Problem
When a relationship's source and target are the same collection (e.g.
regions.parentRegionId → regions.id), the correlated subquery was aliased with the same name as the outer table scan. MySQL resolved both sides of the JOIN condition to the inner scope, turning:into a tautological self-comparison that always returned no rows — with no error surfaced in GraphQL or connector logs.
Note: PR #88 fixed the same issue for Snowflake and Trino (
CTEQueryGenerator.kt). This PR applies the equivalent fix to MySQL (JSONGenerator.kt).Fix
Derive a unique inner alias from the field alias and target collection name (e.g.
parentRegion_regions) and pass it through to:FROMclause alias (FROM regions AS parentRegion_regions)mkJoinWhereClause(WHERE regions.FK = parentRegion_regions.PK)getSelectOrderFields/getConcatOrderFields/translateIROrderByFieldexpressionToCondition(predicate field references inside the subquery)collectRequiredJoinTablesForWhereClauserootTableargasTable()Cross-table relationships are unaffected — existing behaviour is preserved by the defaulted
innerAliasparameter onmkJoinWhereClause.Test
Adds
ndc-ir/src/test/resources/queryRequests/self_referential_object_relationship.json— a query fixture for the self-referential object relationship case (regions → parentRegionviaparentRegionId → idon the same table).Verification
Verified end-to-end in a local DDN project:
ghcr.io/hasura/ndc-jvm-mysql:v1.0.18){ regions { id name parentRegionId parentRegion { id name } } }— all non-root rows resolvedparentRegioncorrectly (previously all returnednull)