대부분의 MySQL에서 PostgreSQL 변환기가 고장나는 이유와 실제 엔진이 고치는 방법

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:

1. Loads your dump into an isolated database sandbox (real MySQL 8.0 or PostgreSQL 16)
2. Converts engine-to-engine — schema is read from the live catalog, not from text
3. 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.