LocalSQL Client Documentation

A high-performance, client-side SQL development workspace running 100% in your browser using SQLite compiled to WebAssembly (sql.js).

💾 Database Operations

Manage multiple SQLite databases with instant switching and file synchronization.

⚡ SQL Query Editor

The code editor is designed specifically for efficient SQL query drafting and execution.

Core Editing Features:

• Execution Modes: Run the entire query canvas, or highlight specific text to execute Run Selection.
• Keyboard Shortcut: Press Ctrl + Enter (or Cmd + Enter on Mac) to execute instantly.
• Code Indentation: Pressing Tab inserts a clean 2-space tab indentation.
• Keyword Formatter: Click Format to uppercase all standard SQL keywords (SELECT, FROM, JOIN, WHERE, etc.).
• Context Sample Queries: When browsing sample databases, access pre-built sample queries from the dropdown.

📊 Results & Inspection

Interactive tabular presentation with execution metrics and export capabilities.

Result Grid Features:

• Execution Speed: High-precision query runtime displayed in milliseconds (e.g. 1.4 ms).
• Live In-Table Search: Instant filter input searches across all visible columns without re-querying the database.
• Click-to-Copy: Click any table cell to immediately copy its value to the clipboard.
• Formatted Values: Distinct badges for NULL values and right-aligned numeric data.
• Pagination: Browse results with 10, 25, 50, or 100 rows per page.
• Data Export: One-click download of result sets to CSV or JSON.

🗄️ Sidebar & Schema Explorer

Inspect schema, insert snippets, and trace recent query executions.

• Tables & Columns: View all tables with live row counts. Expand tables to inspect column names, data types, and primary key badges.
• Quick Query: Click any table name in the sidebar to auto-generate and run SELECT * FROM table LIMIT 50;.
• Snippets Tab: Pre-built snippets for joins, aggregations, and table creation.
• History Tab: Chronological log of executed queries with timestamps and one-click rerun.

🏛️ SQL Support Matrix: Triggers, Procedures & Functions

Understanding SQLite WebAssembly engine capabilities and alternatives:

⚡ Multi-Statement Scripts & ACID Transactions

Because SQLite does not have stored procedures, you can achieve procedure-like transactional workflows by grouping multiple statements inside a single transaction script:

-- Multi-Statement Transaction
BEGIN TRANSACTION;

UPDATE accounts SET balance = balance - 100 WHERE id = 1 AND balance >= 100;
UPDATE accounts SET balance = balance + 100 WHERE id = 2;
INSERT INTO transfer_logs (from_id, to_id, amount) VALUES (1, 2, 100);

COMMIT;

• Atomicity: If any statement fails or produces a syntax error, no intermediate updates are persisted.
• High Performance: Multi-statement transactions execute up to 100x faster than single-statement autocommits.
• Explicit Rollback: You can explicitly execute ROLLBACK; to discard changes if a condition check fails.

📚 Built-in Functions Reference

Standard SQLite functions you can call directly in queries:

⌨️ Keyboard Shortcuts Reference

📋 Common SQL Recipes

Copy any of the following queries to paste and execute inside LocalSQL Client:

1. Create Table with Constraints

CREATE TABLE IF NOT EXISTS notes (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  title TEXT NOT NULL,
  content TEXT,
  created_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

2. Aggregate Orders with Total Revenue

SELECT 
  c.first_name || ' ' || c.last_name AS customer_name,
  c.city,
  COUNT(o.id) AS total_orders,
  ROUND(SUM(o.total_amount), 2) AS total_spent
FROM customers c
JOIN orders o ON c.id = o.customer_id
GROUP BY c.id
ORDER BY total_spent DESC;

3. Department Headcount & Salary Summary

SELECT 
  d.name AS department,
  COUNT(e.id) AS employee_count,
  ROUND(AVG(e.salary), 2) AS avg_salary,
  ROUND(SUM(e.salary), 2) AS total_payroll
FROM departments d
LEFT JOIN employees e ON d.id = e.department_id
GROUP BY d.id
ORDER BY total_payroll DESC;