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SQL Server to MySQL migration guide

Convert a SQL Server script from SSMS into a MySQL script with the same tables, keys and data: how to script, convert, load, and every rule applied.

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IntoSQL reads the script SSMS writes with Generate Scripts and writes one MySQL script with the same tables, columns, keys, indexes, foreign keys, defaults, counters, comments and rows. It reads the script itself, without a database server, and lists in the report every value MySQL can't hold as it is and every object it doesn't carry. The script loads on MySQL 5.7 and later.

Convert in the browser: SQL Server to MySQL opens the converter set up for this pair.

Script for the best result

In SQL Server Management Studio, right-click the database, choose Tasks, Generate Scripts, pick the tables, and under Advanced set Types of data to script to Schema and data. Save it as Unicode (SSMS's default) or UTF-8, as .sql or .sql.gz. dbatools (Export-DbaScript), mssql-scripter and other tools built on SQL Server Management Objects write the same script, from SQL Server 2017 on.

  • A script of the data alone still converts: the types are read from the values, and the report says the schema was missing (no_schema).
  • Tables on a partition scheme arrive as one table with every partition's rows (partitions_dropped), and a temporal table and its history table arrive as two plain tables.
  • SSMS doesn't script the values of computed and rowversion columns; computed columns are written again, and rowversion columns are reported (rowversion_empty).

Convert

In the browser, open SQL Server to MySQL or the converter on the home page, drop the script and choose MySQL. It reads the file from your disk in pieces, twice, and writes the new script as it goes, so the file is never uploaded and its size isn't limited by memory. The desktop app does the same with the file on disk.

With the command line:

Terminal
intosql inspect shop.sql
intosql convert shop.sql --to mysql --output shop.mysql.sql --report shop.report.json

inspect lists the tables, their rows and what won't be converted, without writing anything. convert writes the script and, with --report, the report as JSON.

Through the API, a script converts like any other file: open a conversion with its name ending in .sql or .sql.gz and "output": {"dialect": "mysql"}.

Load into MySQL

Terminal
mysql -e "CREATE DATABASE shop"
mysql --default-character-set=utf8mb4 shop < shop.mysql.sql

The script sets the character set and a binary collation, then creates each table with its keys and copies the rows with foreign key and unique checks off. Schemas other than dbo become a prefix on their tables' names (app.orders is app_orders). The IDENTITY column that leads each primary key becomes AUTO_INCREMENT and continues after the highest id. datetimeoffset values are stored as datetime in UTC (moments_as_utc), and datetime2 keeps six digits of a second (fraction_cut). Columns with a collation that ignores case compare exactly, so unique keys keep apart what SQL Server kept apart, and the report says how many there are (case_insensitive_collation). MySQL has no sequences (sequence_not_converted).

Or load it straight in

intosql load and the desktop app load the dump into MySQL without a script, with the same tables, keys and indexes the script creates:

Terminal
intosql load shop.sql --into mysql://ana@localhost/shop

It stops before writing anything when one of the dump's tables already exists. MySQL can't roll back a table, so a failed load drops the tables it created. Loading into a database server is part of IntoSQL Pro, with a 14-day trial. See Loading.

What isn't converted

Views, functions, procedures, triggers, synonyms, rules and security policies are written in T-SQL. They are listed in the report by kind and name, never dropped silently, so you can recreate them in MySQL.

Data types

SQL Server to MySQL data types lists each type that changes in the script: what it becomes, why, and the report line.

Every other rule

Generated from the engine, where each rule is decided.

In SQL Server In MySQL Why Report line
collations that ignore case (CI) exact comparison (utf8mb4_bin) Tables use utf8mb4_bin so unique keys keep apart what SQL Server kept apart; columns that ignored case lose that. Accent rules differ between versions, so no _ci collation matches SQL Server's on every one. case_insensitive_collation
CREATE SEQUENCE not created MySQL has no sequences. The values a sequence handed out are in the rows. sequence_not_converted
computed columns generated columns, STORED when PERSISTED, VIRTUAL otherwise MySQL computes them the same two ways, with CONCAT written so NULL counts as empty as in SQL Server. None
computed columns with functions MySQL lacks a plain column A formula that can't be written leaves a plain column and a report line; SSMS scripts no values for computed columns. generated_not_translated
defaults with functions MySQL lacks, and NEXT VALUE FOR no default A default that can't be written is left out and reported. default_not_translated
CHECK constraints translated MySQL 5.7 keeps them without checking; the others test them as each row loads. None
CHECK constraints with functions MySQL lacks not created A check that can't be written is left out and reported. check_skipped
CHECK constraints added WITH NOCHECK or disabled not created SQL Server doesn't apply these checks, so the rows may break them. check_not_enforced
filtered and columnstore indexes not created IntoSQL writes b-tree indexes on whole columns; create the others again after loading. index_skipped
foreign keys foreign keys, loaded with FOREIGN_KEY_CHECKS=0 The rows load in any order, and the keys check new rows afterwards. None
foreign keys to tables the dump doesn't create not created A key can't name a table that isn't there. foreign_key_skipped
tables on a partition scheme one table with every partition's rows The rows are the same; partition the table again in MySQL if it needs it. partitions_dropped
temporal tables (SYSTEM_VERSIONING) two tables: the current rows and the history The table and its history table are copied as plain tables; MySQL doesn't keep the history by itself. system_versioning_dropped
schemas one database, tables named after their schema first MySQL's schemas are databases, which a script loaded into one database can't create; tables in dbo keep their names. schemas_merged
NOT NULL columns with values that become NULL NOT NULL dropped A column whose values had to become NULL can't keep NOT NULL, or the load would stop. not_null_relaxed
views, functions, procedures, triggers, synonyms, types and partition functions listed in the report Their code is written in T-SQL, so they are listed for you to recreate. not_converted_objects
scripts without CREATE TABLE (data only) types read from the values A data-only script has only rows, so the types come from the values. no_schema
expressions in INSERT values NULL A converter that doesn't run a database can't evaluate them. expression_value
text decoded twice (ñ) copied as it is The script holds exactly these characters, so they are copied; the report points them out. mojibake_suspected