| name | tidb-sql |
| description | Write, review, and adapt SQL for TiDB with correct handling of TiDB-vs-MySQL differences (VECTOR type + vector indexes/functions, full-text search, AUTO_RANDOM, optimistic/pessimistic transactions, foreign keys, views, DDL limitations, and unsupported MySQL features like procedures/triggers/events/GEOMETRY/SPATIAL). Use when generating SQL that must run on TiDB, migrating MySQL SQL to TiDB, or debugging TiDB SQL compatibility errors. |
TiDB SQL (MySQL-compat-focused)
Goal: generate SQL that runs correctly on TiDB by default, and avoid "works on MySQL but breaks on TiDB" constructs.
Workflow (use every time)
- Identify the target engine and version:
- Run
SELECT VERSION();
- If the result contains
TiDB, treat it as TiDB and parse the version (needed for feature gates like Vector / Foreign Key).
- If connecting to TiDB Cloud, ensure the client enables SSL with certificate + identity verification (see
skills/tidb-sql/references/tidb-cloud-ssl.md).
- Ask 2 quick capability questions if the request depends on them:
- "Do you have TiFlash?" (needed for vector indexes)
- "Is this TiDB Cloud Starter/Essential in a supported region for Full-Text Search?" (availability is limited)
- Generate SQL using TiDB-safe defaults:
- Avoid unsupported MySQL features (procedures/triggers/events/UDF/GEOMETRY/SPATIAL, etc.)
- Treat views as read-only
- Treat primary key changes as migration/rebuild work
- If the user provides MySQL SQL, do a compatibility pass:
- Replace unsupported features with TiDB alternatives
- Call out behavior differences and version prerequisites explicitly
- If SQL is slow or fails unexpectedly, use TiDB-native diagnostics:
- Use
EXPLAIN FORMAT = "tidb_json" for structured plans and operator trees.
- Use
EXPLAIN ANALYZE to compare estRows vs actRows (it executes the query).
- If the plan looks wrong, consider
ANALYZE TABLE ... to refresh statistics.
High-signal differences (keep in mind)
- Vector: TiDB supports
VECTOR / VECTOR(D) types and vector functions/indexes; MySQL does not.
- No GEOMETRY/SPATIAL: avoid
GEOMETRY, spatial functions, and SPATIAL indexes.
- No procedures / functions / triggers / events: move logic to the application layer or an external scheduler.
- Full-text search (TiDB feature): use TiDB full-text search SQL when available; don't assume MySQL
FULLTEXT works everywhere.
- Views are read-only: no
UPDATE/INSERT/DELETE against views.
- Foreign keys: supported in TiDB v6.6.0+; otherwise, don't rely on FK enforcement.
- Primary key changes are restricted: assume "create new table + backfill + swap" for PK changes.
- AUTO_RANDOM: prefer
AUTO_RANDOM over AUTO_INCREMENT for write-hotspot avoidance when appropriate.
- Transactions: TiDB supports pessimistic and optimistic modes; handle optimistic
COMMIT failures in application logic.
Use these references (inside this skill)
skills/tidb-sql/references/vector.md - VECTOR types, functions, vector index DDL, and query patterns.
skills/tidb-sql/references/full-text-search.md - Full-text search SQL patterns and availability gotchas.
skills/tidb-sql/references/auto-random.md - AUTO_RANDOM rules, DDL patterns, and restrictions.
skills/tidb-sql/references/transactions.md - pessimistic vs optimistic mode and session/global knobs.
skills/tidb-sql/references/mysql-compatibility-notes.md - other "MySQL vs TiDB" differences that commonly break SQL.
skills/tidb-sql/references/explain.md - EXPLAIN / EXPLAIN ANALYZE usage, tidb_json and dot formats.
skills/tidb-sql/references/flashback.md - FLASHBACK TABLE/DATABASE and FLASHBACK CLUSTER recovery playbooks.
skills/tidb-sql/references/tidb-cloud-ssl.md - TiDB Cloud SSL verification requirements and client flags.