● SQL CREATE TABLE STATEMENTS · 100% BROWSER-BASED

JSON to SQL

Paste a JSON sample and get SQL CREATE TABLE statements, instantly and entirely in your browser. Optional fields, nullability and nested types are inferred from the sample — and anything the sample cannot settle is reported rather than guessed.

Target Root name

JSON sample

TypeScript interface

Type definitions will appear here

What it generates

Sql create table statements from a sample

Generates one table per object type. A nested object becomes its own table joined by a foreign key, because a relational column cannot hold a nested record. Identifiers that clash with SQL keywords, or that are not valid unquoted, are quoted.

Arrays are stored as JSONB. Whether an array deserves its own table is a modelling decision a sample cannot make for you — as are column lengths and indexes. Review before running.

Limits

What a sample cannot tell you

Types are inferred from one sample. A field absent from your sample will be absent from the output, and a field that happens to hold only whole numbers will be typed as an integer even if it can hold decimals. Paste the widest sample you have. For a guarantee rather than an inference, start from a JSON Schema.

Worked example

What SQL output looks like

Generated from two sample records, one of which has an extra field and a null. This is the actual output, not an illustration:

-- Generated from a JSON sample (PostgreSQL dialect). Review before running:
-- column lengths, indexes, and whether an array deserves its own table
-- are decisions a sample cannot make for you.

CREATE TABLE address (
    id BIGSERIAL PRIMARY KEY,
    city TEXT NOT NULL,
    postcode TEXT
);

CREATE TABLE root (
    id BIGINT PRIMARY KEY,
    user_name TEXT NOT NULL,  -- JSON key: "userName"
    is_active BOOLEAN NOT NULL,  -- JSON key: "isActive"
    score DOUBLE PRECISION NOT NULL,
    tags JSONB NOT NULL,
    address_id BIGINT NOT NULL,
    last_seen TEXT NOT NULL,  -- JSON key: "lastSeen"
    nickname TEXT,
    CONSTRAINT fk_root_address FOREIGN KEY (address_id) REFERENCES address (id)
);

SQL specifics

The three things that differ by language

Large integers

A 64-bit identifier becomes BIGINT. Note that the value shown was already rounded by the browser before it reached the generator — if your ids are near 2⁶³, treat them as strings end to end.

Optional against nullable

A column is NOT NULL only when the field was present and non-null in every sample. Anything else is left nullable, because a sample cannot prove a constraint.

Names that are not identifiers

Identifiers that clash with SQL keywords, or that are not valid unquoted, are double-quoted. A nested object becomes its own table joined by a foreign key, because a relational column cannot hold a nested record.

Other targets