Quick Start

This guide walks you through common loq operations with hands-on examples.

Basic Query Syntax

The basic command structure is:

loq [options] "SQL_QUERY"

The SQL query follows standard syntax:

SELECT columns FROM 'file' WHERE condition ORDER BY column LIMIT n

Your First Query

Create a sample CSV file:

cat > users.csv << 'EOF'
name,age,city,salary
Alice,32,New York,75000
Bob,28,San Francisco,85000
Carol,35,Chicago,70000
David,42,New York,95000
Eve,29,San Francisco,80000
EOF

Query all data:

loq "SELECT * FROM users.csv"

Output:

name,age,city,salary
Alice,32,New York,75000
Bob,28,San Francisco,85000
Carol,35,Chicago,70000
David,42,New York,95000
Eve,29,San Francisco,80000

Selecting Columns

Select specific columns:

loq "SELECT name, city FROM users.csv"

Output:

name,city
Alice,New York
Bob,San Francisco
Carol,Chicago
David,New York
Eve,San Francisco

Filtering with WHERE

Filter rows by condition:

loq "SELECT name, salary FROM users.csv WHERE salary > 75000"

Output:

name,salary
Bob,85000
David,95000
Eve,80000

Multiple conditions:

loq "SELECT * FROM users.csv WHERE city = 'New York' AND age > 30"

Sorting with ORDER BY

Sort results:

loq "SELECT name, salary FROM users.csv ORDER BY salary DESC"

Output:

name,salary
David,95000
Bob,85000
Eve,80000
Alice,75000
Carol,70000

Limiting Results

Get top N results:

loq "SELECT name, salary FROM users.csv ORDER BY salary DESC LIMIT 3"

Aggregation

COUNT

loq "SELECT COUNT(*) as total FROM users.csv"

GROUP BY

loq "SELECT city, COUNT(*) as count, AVG(salary) as avg_salary
           FROM users.csv
           GROUP BY city"

Output:

city,count,avg_salary
Chicago,1,70000
New York,2,85000
San Francisco,2,82500

HAVING

Filter aggregated results:

loq "SELECT city, COUNT(*) as count
           FROM users.csv
           GROUP BY city
           HAVING COUNT(*) > 1"

Using Functions

String Functions

loq "SELECT UPPER(name) as NAME, LOWER(city) as city FROM users.csv"

Math Functions

loq "SELECT name, ROUND(salary / 1000, 1) as salary_k FROM users.csv"

Conditional Functions

loq "SELECT name,
                  IF(salary > 80000, 'High', 'Normal') as level
           FROM users.csv"

Different Input Formats

JSON

cat > data.json << 'EOF'
{"name": "Alice", "score": 95}
{"name": "Bob", "score": 87}
{"name": "Carol", "score": 92}
EOF

loq -i:JSON "SELECT name, score FROM data.json WHERE score > 90"

Web Server Logs (W3C)

loq -i:W3C "SELECT date, cs-uri-stem, sc-status
                  FROM access.log
                  WHERE sc-status >= 400"

Windows Event Logs

loq -i:EVTX "SELECT TimeCreated, EventID, Message
                   FROM System.evtx
                   WHERE Level <= 2
                   ORDER BY TimeCreated DESC
                   LIMIT 10"

Filesystem

loq -i:FS "SELECT Name, Size, LastModified
                 FROM '/var/log'
                 WHERE Extension = 'log'
                 ORDER BY Size DESC
                 LIMIT 10"

Output Formats

JSON Output

loq -o:JSON "SELECT * FROM users.csv LIMIT 2"

Output:

{"name":"Alice","age":32,"city":"New York","salary":75000}
{"name":"Bob","age":28,"city":"San Francisco","salary":85000}

Table Output (DATAGRID)

loq -o:DATAGRID "SELECT name, city, salary FROM users.csv"

Output:

+-------+---------------+--------+
| name  | city          | salary |
+-------+---------------+--------+
| Alice | New York      | 75000  |
| Bob   | San Francisco | 85000  |
| Carol | Chicago       | 70000  |
| David | New York      | 95000  |
| Eve   | San Francisco | 80000  |
+-------+---------------+--------+

SQLite Output

loq -o:SQLITE --ofile:output.db "SELECT * FROM users.csv"

Chart Output

loq -o:CHART -chartType:Bar -chartTitle:"Salary by City" \
          --ofile:salary.png \
          "SELECT city, AVG(salary) FROM users.csv GROUP BY city"

JOINs

Create related tables:

cat > departments.csv << 'EOF'
dept_id,dept_name
1,Engineering
2,Marketing
3,Sales
EOF

cat > employees.csv << 'EOF'
name,dept_id,salary
Alice,1,75000
Bob,1,85000
Carol,2,70000
David,3,95000
EOF

Join them:

loq "SELECT e.name, d.dept_name, e.salary
           FROM employees.csv e
           INNER JOIN departments.csv d ON e.dept_id = d.dept_id"

Output:

name,dept_name,salary
Alice,Engineering,75000
Bob,Engineering,85000
Carol,Marketing,70000
David,Sales,95000

Window Functions

loq "SELECT name, salary,
                  RANK() OVER (ORDER BY salary DESC) as rank
           FROM users.csv"

Output:

name,salary,rank
David,95000,1
Bob,85000,2
Eve,80000,3
Alice,75000,4
Carol,70000,5

Common Patterns

Count by Category

loq "SELECT status, COUNT(*) FROM logs.csv GROUP BY status ORDER BY COUNT(*) DESC"

Find Duplicates

loq "SELECT email, COUNT(*) as count
           FROM users.csv
           GROUP BY email
           HAVING COUNT(*) > 1"

Recent Records

loq "SELECT * FROM logs.csv ORDER BY timestamp DESC LIMIT 100"

Top N by Group

loq "SELECT name, city, salary,
                  ROW_NUMBER() OVER (PARTITION BY city ORDER BY salary DESC) as rank
           FROM users.csv"

Next Steps

• SQL Reference - Full SQL syntax documentation
• Functions - All built-in functions
• Input Formats - Detailed format documentation
• CLI Reference - All command-line options