JSON to SQL

How to use JSON to SQL

1. Paste a JSON array of objects (or a single object) into Input JSON, drop a file on it, or use Open file. Try an example loads a sample.
2. Choose the Dialect: PostgreSQL, MySQL, SQLite or SQL Server, and set the Table name (schema.table works too).
3. Set Rows per INSERT, optionally pick a Primary key column, and untick Include CREATE TABLE if you only want the inserts.
4. Check the inferred types in the Columns panel and any warnings, then copy the SQL, use Download .sql, or send it to another tool.

How it works

The JSON is read with the same strict parser as the JSON Formatter, which keeps numbers exactly as written. Each object is a row, and the columns are every key that appears, in the order first seen. A row without a key gets NULL there. Nested objects and arrays are not flattened; they are stored as JSON text.

Each column’s type comes from all of its values. Whole numbers become INTEGER/INT, BIGINT or an exact NUMERIC/DECIMAL depending on their range. Decimals become NUMERIC(p, s)/DECIMAL(p, s) sized to the widest value, and exponent numbers a floating-point type. Strings that are ISO dates (2024-01-15) become DATE, and date-times become TIMESTAMP, TIMESTAMPTZ when they have an offset, DATETIME, DATETIME2 or DATETIMEOFFSET, depending on the dialect. Other strings become VARCHAR(n) (16, 32, 64, 128 or 255) or TEXT, objects and arrays JSONB/JSON, and booleans BOOLEAN, BIT or INTEGER. A column with mixed kinds of values is stored as text. SQLite gets its own simpler types. Columns with a value in every row are marked NOT NULL.

Every identifier is quoted with the quote character doubled: double quotes for PostgreSQL and SQLite, backticks for MySQL and [name] for SQL Server, and every string is escaped for the chosen dialect. MySQL gets backslash escapes, SQL Server N'…' literals, and NUL characters are written as char(0) or NCHAR(0) (or removed for PostgreSQL). Numbers are written exactly as they appear in the JSON. Booleans are TRUE/FALSE, or 1/0 for SQLite and SQL Server. For MySQL, date-times with an offset are converted to UTC because DATETIME has no time zone. Conversion runs in the page as you type.

Limits

• Input is limited to about 10 MB (10 million characters); opened or dropped files to 10 MB. Only the first 1 MB of SQL is shown on screen; copy or download to get all of it.
• Rows per INSERT are capped at 10,000 for PostgreSQL and MySQL, 500 for SQLite and 1,000 for SQL Server, with a warning when your number is higher.
• Only CREATE TABLE and INSERT are generated: no indexes, foreign keys, upserts or DROP TABLE.
• The input must be an array of objects or a single object. An item that isn’t an object, such as a number or an array, is reported as an error.
• Dates are only recognised in ISO form (YYYY-MM-DD, optionally with a time). Nested objects aren’t split into separate columns or tables.
• If an object has a key twice, the last value is used. An empty key becomes a column named column.
• The MySQL output assumes the default sql_mode. It won’t load correctly with NO_BACKSLASH_ESCAPES.

Privacy

SQL is generated entirely in your browser; your JSON is never uploaded or stored, and there is no share link. If you use Send to… to open the SQL in another tool, or receive JSON from one, it is handed over through this tab’s session storage and removed as soon as the receiving tool reads it.

Frequently asked questions

Is the generated SQL safe from injection?

Every value is turned into a literal by the tool rather than pasted in. Identifiers are always quoted with the quote character doubled, strings are escaped for the chosen dialect, and numbers are only ever valid JSON number text. Hostile keys, table names and values stay inside their literals.

How are nested objects and arrays stored?

As JSON text in a single column, typed JSONB in PostgreSQL, JSON in MySQL, TEXT in SQLite and NVARCHAR(MAX) in SQL Server. They are not flattened into extra columns.

Why is a column TEXT instead of a number?

The column holds more than one kind of value, for example numbers in some rows and strings in others, so it’s stored as text to keep every value. Values that are null or missing don’t count. They only make the column nullable.

Are big numbers and decimals kept exactly?

Yes. Numbers are written exactly as in the JSON, so long IDs and amounts like 120.50 aren’t rounded. Integers beyond 64 bits get an exact NUMERIC/DECIMAL type where the dialect allows it.

What does the Primary key option check?

The chosen column is marked PRIMARY KEY in the CREATE TABLE. You get a warning if it’s missing or null in some rows or has duplicate values. For text keys, SQL Server and MySQL get a bounded type such as NVARCHAR(450) or VARCHAR(768) so the key can be indexed.