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JSON to SQL Converter: Generate INSERT Statements

Published 5 min read
In this article

Why Convert JSON to SQL?

JSON is the standard format for APIs, configuration files, and data interchange, but relational databases speak SQL. When you need to import JSON data into MySQL, PostgreSQL, SQLite, or SQL Server, you need INSERT statements. Manually writing SQL for hundreds or thousands of records is tedious and error-prone.

A JSON to SQL converter automates this by analyzing your JSON structure, inferring column types, and generating valid INSERT statements ready to execute. This is useful for seeding development databases, migrating data between systems, and importing API responses into a relational database for analysis.

How the Converter Works

The converter analyzes your JSON array of objects and transforms each object into an SQL INSERT statement with proper type handling.

  • Structure analysis -- examines all objects to collect the complete set of keys, since different objects may have different properties
  • Type detection -- infers SQL column types from the JSON values: strings become VARCHAR or TEXT, numbers become INT or DECIMAL, booleans become BOOLEAN, and null values are preserved as NULL
  • SQL generation -- produces INSERT INTO statements with properly quoted values, escaped strings, and correct NULL handling for the target database dialect

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Options Explained

The converter provides several options to control the generated SQL output for different database systems and use cases.

  • CREATE TABLE -- optionally generates a CREATE TABLE statement with inferred column types before the INSERT statements, useful for creating the table and importing data in one step
  • Batch INSERT -- groups multiple rows into a single INSERT statement using multi-value syntax (INSERT INTO table VALUES (...), (...), (...)) for better performance when importing large datasets
  • Identifier quoting -- controls how table and column names are quoted: backticks for MySQL, double quotes for PostgreSQL and standard SQL, or square brackets for SQL Server
  • Table name -- lets you specify the target table name instead of using a default, so the generated SQL is ready to execute against your actual database schema

Frequently Asked Questions

How does the converter map JSON types to SQL types?

JSON strings are mapped to VARCHAR(255) or TEXT depending on length. JSON numbers are mapped to INT for integers and DECIMAL for numbers with decimal points. JSON booleans are mapped to BOOLEAN (or TINYINT(1) for MySQL). JSON null values produce NULL in the SQL output. Nested objects and arrays are serialized as JSON strings in the SQL column.

How are NULL values handled?

JSON null values and missing keys both produce SQL NULL values in the INSERT statements. The converter checks each object for missing properties and fills them with NULL to ensure all INSERT statements have the same number of columns. This matches standard SQL behavior where NULL means the value is unknown or not applicable.

How are strings with special characters escaped?

Strings containing single quotes are escaped by doubling the quote character ('O''Brien'). Backslashes, newlines, and other special characters are handled according to the target SQL dialect. This prevents SQL injection in the generated statements and ensures the SQL is syntactically valid.

Can it handle nested JSON objects?

Nested objects and arrays within your JSON data are serialized as JSON strings in the corresponding SQL column. If you need nested data in separate tables with foreign key relationships, you would need to flatten the JSON structure first or use a more specialized ETL tool. The converter handles one level of objects to SQL rows mapping.

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