incomplete input

This error occurs when your SQL statement is cut off or missing required parts. Common with missing closing parentheses, quotes, or semicolons.

The incomplete input error means SQLite received a partial SQL statement.

Understanding the Error

Error: incomplete input

The SQL statement is syntactically incomplete - something is missing at the end.

Common Causes

1. Missing Closing Parenthesis

SQL

-- Wrong: unclosed parenthesis
INSERT INTO users VALUES (1, 'Alice'

-- Correct
INSERT INTO users VALUES (1, 'Alice');

2. Missing Closing Quote

SQL

-- Wrong: unclosed string
SELECT * FROM users WHERE name = 'Alice

-- Correct
SELECT * FROM users WHERE name = 'Alice';

3. Missing Semicolon

SQL

-- Wrong: no semicolon (some contexts)
SELECT * FROM users

-- Correct
SELECT * FROM users;

4. Incomplete CREATE Statement

SQL

-- Wrong: incomplete
CREATE TABLE users (
  id INTEGER PRIMARY KEY,
  name TEXT

-- Correct
CREATE TABLE users (
  id INTEGER PRIMARY KEY,
  name TEXT
);

5. Multi-Line String Issues

JAVASCRIPT

// Wrong: template literal issue
const sql = `SELECT * FROM users
             WHERE name = 'O'Brien'`;  // Quote breaks the SQL

// Correct: escape or use parameters
const sql = `SELECT * FROM users WHERE name = ?`;
db.get(sql, ["O'Brien"]);

How to Fix It

Solution 1: Check Parentheses Balance

JAVASCRIPT

function checkParentheses(sql) {
  let count = 0;
  for (const char of sql) {
    if (char === '(') count++;
    if (char === ')') count--;
    if (count < 0) return false;
  }
  return count === 0;
}

if (!checkParentheses(sql)) {
  console.error('Unbalanced parentheses');
}

Solution 2: Check Quote Balance

JAVASCRIPT

function checkQuotes(sql) {
  let inSingle = false;
  let inDouble = false;

  for (let i = 0; i < sql.length; i++) {
    const char = sql[i];
    const prev = sql[i - 1];

    if (char === "'" && prev !== '\\' && !inDouble) {
      inSingle = !inSingle;
    }
    if (char === '"' && prev !== '\\' && !inSingle) {
      inDouble = !inDouble;
    }
  }

  return !inSingle && !inDouble;
}

Solution 3: Use SQL Formatter

JAVASCRIPT

const sqlFormatter = require('sql-formatter');

// Format SQL to spot issues
console.log(sqlFormatter.format(sql));

Solution 4: Build SQL Safely

JAVASCRIPT

// Use query builders to avoid syntax errors
const knex = require('knex')({ client: 'sqlite3' });

const query = knex('users')
  .select('*')
  .where('name', 'Alice')
  .toString();

Solution 5: Validate Before Executing

JAVASCRIPT

function validateSQL(sql) {
  // Quick checks
  if (!sql.trim().endsWith(';')) {
    console.warn('SQL might be missing semicolon');
  }

  const openParens = (sql.match(/\(/g) || []).length;
  const closeParens = (sql.match(/\)/g) || []).length;
  if (openParens !== closeParens) {
    throw new Error(`Unbalanced parentheses: ${openParens} open, ${closeParens} close`);
  }
}

Debugging Tips

JAVASCRIPT

// Log the exact SQL being executed
console.log('Executing SQL:', JSON.stringify(sql));

// Check for hidden characters
console.log('SQL bytes:', Buffer.from(sql).toString('hex'));

Best Practices

Use parameterized queries for user input
Use query builders for complex queries
Format SQL for readability
Validate SQL before execution
Test with sample data before production