Memgraph ZeroMemGQLConnectto MySQL

MySQL

The MySQL connector (CONNECTOR_TYPE=mysql) translates GQL queries into MySQL-dialect SQL and executes them against MySQL 8.0+. It requires a mapping file that maps graph patterns to relational tables.

1. Start MySQL

docker network create memgql-net
 
docker run -d --rm \
    --name mysql-dev \
    --network memgql-net \
    -p 3306:3306 \
    --env MYSQL_ROOT_PASSWORD=mysql \
    --env MYSQL_DATABASE=test \
    mysql:9

2. Seed data

docker exec -i mysql-dev mysql -uroot -pmysql test << 'SQL'
CREATE TABLE IF NOT EXISTS persons (
    id   INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    age  INT
) ENGINE=InnoDB;
 
CREATE TABLE IF NOT EXISTS companies (
    id   INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(255) NOT NULL
) ENGINE=InnoDB;
 
CREATE TABLE IF NOT EXISTS knows (
    from_id INT NOT NULL,
    to_id   INT NOT NULL,
    FOREIGN KEY (from_id) REFERENCES persons(id),
    FOREIGN KEY (to_id)   REFERENCES persons(id)
) ENGINE=InnoDB;
 
CREATE TABLE IF NOT EXISTS works_at (
    person_id  INT NOT NULL,
    company_id INT NOT NULL,
    FOREIGN KEY (person_id)  REFERENCES persons(id),
    FOREIGN KEY (company_id) REFERENCES companies(id)
) ENGINE=InnoDB;
 
INSERT INTO persons (id, name, age) VALUES (1, 'Alice', 30), (2, 'Bob', 25);
INSERT INTO companies (id, name) VALUES (1, 'Acme Corp');
INSERT INTO knows (from_id, to_id) VALUES (1, 2);
INSERT INTO works_at (person_id, company_id) VALUES (1, 1);
SQL

3. Start MemGQL

docker run --rm \
    --name memgql \
    --network memgql-net \
    --stop-timeout 2 \
    -p 7688:7688 \
    --env CONNECTOR_TYPE=mysql \
    --env MYSQL_URL="mysql://root:mysql@mysql-dev:3306/test" \
    --env MAPPING_FILE=/data/mapping.json \
    --env BOLT_LISTEN_ADDR=0.0.0.0:7688 \
    -v ./mapping.json:/data/mapping.json \
    memgraph/memgql:latest

4. Connect

mgconsole --port 7688

5. Query

MATCH (p:Person) RETURN p.name, p.age;
MATCH (p:Person)-[:WORKS_AT]->(c:Company) RETURN p.name, c.name;
MATCH (a:Person)-[:KNOWS]->(b:Person) RETURN a.name, b.name;

Dialect notes

  • Positional ? parameter placeholders (no numbered $1 form).
  • No RETURNING on INSERT — use last_insert_id() if you need the generated row id.
  • Aliased single-table DELETE is emitted as the multi-table form DELETE alias FROM table AS alias WHERE … (MySQL 8.0+ requirement).

For environment variables, see Reference.

Supported GQL features

FeatureMySQL
MATCH / WHERE / RETURN✓
Pattern-level WHERE (MATCH (n WHERE …))✓
Multi-MATCH (cross-join)✓
OPTIONAL MATCH✓
WITH pipeline boundary✓
WITH DISTINCT / WITH … ORDER BY … LIMIT N✓
Chained WITH … WITH …✓
Whole-node WITH n carry-through✓
Typed edge (a)-[r:R]->(b)✓
Untyped edge ()-[]->(b)✓
UNION / UNION ALL / UNION DISTINCT✓
Quantified path (){m,n} — bounded✓
Map projections RETURN n {.a, .b}✓
IN list membership WHERE x IN [...]✓
STARTS WITH / ENDS WITH / CONTAINS✓
collect() aggregate✓
count, sum, avg, min, max✓
COUNT(DISTINCT …)✓
Arithmetic + - * / %✓
CASE WHEN … THEN … ELSE … END✓
COALESCE, NULLIF✓
INSERT (a {…}) (MySQL has no RETURNING)✓
DELETE✓
SET / REMOVE (property update / delete)✗
DETACH DELETE✗
INTERSECT / EXCEPT✗
Quantified path (){m,} — unbounded✗
Shortest-path (ALL SHORTEST / SHORTEST k)✗

Known limitations

  • Unbounded variable-length paths (()-[*]->()) are rejected. Bound the depth ({1,5}) or run the query against a Cypher backend.
  • MATCH p = (...) path binding on quantified traversals is not supported. Drop the path binding or run on a Cypher backend.
  • Whole-node RETURN n projects scalar columns rather than a Bolt Node struct. Use a map projection (RETURN n {.id, .name} AS info) for a single structured cell.
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