Why most MySQL to PostgreSQL converters break — and how real engines fix it

Hamidi Rasim — Mon, 22 Jun 2026 11:36:28 +0000

If you've ever tried converting a MySQL database to PostgreSQL (or the reverse), you've probably run into tools that do text replacement on your SQL dump.

They work fine — until they don't.

Where regex converters fail

The edge cases pile up fast:

Zero dates (0000-00-00) — PostgreSQL rejects them outright
AUTO_INCREMENT — needs to become a proper sequence with the counter set to the right value
ENUM columns — most tools skip them or flatten to VARCHAR
Backtick quoting — mixed with double quotes causes silent breakage
Character sets — Latin1 columns with emoji data get mangled

You only discover these after importing into production and seeing broken data.

A different approach

I built SwapSQL to solve this. Instead of parsing SQL text with regex, it:

Loads your dump into an isolated database sandbox (real MySQL 8.0 or PostgreSQL 16)
Converts engine-to-engine — schema is read from the live catalog, not from text
Exports a clean .sql file from the target engine

The output is guaranteed-valid SQL because it comes from a real database, not a string manipulation script.

The reverse direction: PostgreSQL to MySQL

This is the direction almost nobody supports well. PostgreSQL has types that don't exist in MySQL:

PostgreSQL	MySQL	Notes
`uuid`	`CHAR(36)`	`gen_random_uuid()` default maps to `(uuid())`
`jsonb`	`JSON`	Queryable with MySQL JSON functions
`arrays`	`JSON`	Stored as JSON arrays
`timestamptz`	`DATETIME(6)`	Converted to UTC, microsecond precision kept
`identity/serial`	`AUTO_INCREMENT`	Counter continues from highest existing id

SwapSQL handles all of these, and the PostgreSQL-to-MySQL output is validated by loading it into a real MySQL server before you download it.

Free tier

Dumps up to 10 MB convert for free, no account needed. SQL compresses roughly 10x, so .sql.gz files are accepted — the free tier effectively covers ~100 MB of raw SQL.

Try it: swapsql.com

If you've dealt with MySQL/PostgreSQL migrations, I'd like to hear what pain points you ran into.

DEV Community: Hamidi Rasim

Why most MySQL to PostgreSQL converters break — and how real engines fix it

Where regex converters fail

A different approach

The reverse direction: PostgreSQL to MySQL

Free tier