Learn N1QL with Real Code Examples

SELECT name, email
FROM users
WHERE age > 30;

INSERT INTO users (KEY, VALUE)
VALUES ("user_123", { "name": "Bob", "email": "bob@example.com" });

Querying JSON documents in Couchbase using N1QL.

-- Inner Join
SELECT orders.id, users.name
FROM orders
INNER JOIN users ON orders.user_id = users.id;

-- Left Join
SELECT orders.id, users.name
FROM orders
LEFT JOIN users ON orders.user_id = users.id;

Examples of INNER JOIN and LEFT JOIN queries.

db.orders.aggregate([
    { $match: { status: "completed" } },
    { $group: { _id: "$customerId", total: { $sum: "$amount" } } },
    { $sort: { total: -1 } }
])

Aggregation examples using MongoDB pipelines.

SELECT name, salary,
    ROW_NUMBER() OVER (ORDER BY salary DESC) AS row_num,
    RANK() OVER (ORDER BY salary DESC) AS rank
FROM employees;

Using window functions like ROW_NUMBER and RANK in PostgreSQL.

# Add scores
ZADD leaderboard 100 "Alice"
ZADD leaderboard 200 "Bob"

# Get top players
ZREVRANGE leaderboard 0 -1 WITHSCORES

Working with sorted sets in Redis.

BEGIN BATCH
    INSERT INTO users (id, name, age) VALUES (uuid(), 'Alice', 29);
    INSERT INTO users (id, name, age) VALUES (uuid(), 'Bob', 35);
APPLY BATCH;

Using batch operations in Cassandra with CQL.

MATCH p = (a:Person {name: "Alice"})-[:FRIEND*1..3]->(b:Person)
RETURN a, b, p;

Querying paths between nodes in Neo4j.

-- Create index
CREATE INDEX idx_users_email ON users(email);

-- Query using index
SELECT * FROM users WHERE email = 'bob@example.com';

Creating and using indexes in SQLite.

{
    "query": {
        "match": {
        "description": "fast database"
        }
    }
}

Performing a full-text match query in Elasticsearch.

SELECT MEAN(value)
FROM cpu_usage
WHERE time > now() - 1h
GROUP BY time(5m);

Querying averages and grouping by time intervals in InfluxDB.