SQL Dialect Cheat Sheet: MySQL, PostgreSQL, SQLite, SQL Server and BigQuery

Every major database speaks SQL — but each has its own dialect. This cheat sheet covers the most common syntax differences across all five major databases so you can write the right query the first time.

Identifier Quoting

Database	Style	Example
MySQL / MariaDB	Backticks	users
PostgreSQL	Double quotes	"users"
SQLite	Double quotes or backticks	"users"
SQL Server	Square brackets	[users]
BigQuery	Backticks	project.dataset.users

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Auto-Increment / Identity Columns

-- MySQL
id INT AUTO_INCREMENT PRIMARY KEY

-- PostgreSQL
id SERIAL PRIMARY KEY

-- SQLite
id INTEGER PRIMARY KEY

-- SQL Server
id INT IDENTITY(1,1) PRIMARY KEY

-- BigQuery
id STRING DEFAULT (GENERATE_UUID())

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Boolean Type

-- MySQL
is_active TINYINT(1) DEFAULT 1

-- PostgreSQL
is_active BOOLEAN DEFAULT TRUE

-- SQLite
is_active INTEGER DEFAULT 1

-- SQL Server
is_active BIT DEFAULT 1

-- BigQuery
is_active BOOL DEFAULT TRUE

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NULL Fallback Functions

-- MySQL + SQLite
IFNULL(column, 'default')

-- SQL Server
ISNULL(column, 'default')

-- PostgreSQL + BigQuery + Standard SQL
COALESCE(column, 'default')

COALESCE works across all databases and accepts multiple arguments — use it when writing portable SQL.

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String Concatenation

-- MySQL + SQL Server
CONCAT(first_name, ' ', last_name)

-- PostgreSQL + SQLite + BigQuery
first_name || ' ' || last_name

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Current Timestamp

-- MySQL + PostgreSQL + BigQuery
NOW()

-- SQL Server
GETDATE()

-- SQLite
datetime('now')

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Skip Duplicate Inserts

-- MySQL
INSERT IGNORE INTO users (email) VALUES ('a@b.com');

-- PostgreSQL
INSERT INTO users (email) VALUES ('a@b.com')
ON CONFLICT DO NOTHING;

-- SQLite
INSERT OR IGNORE INTO users (email) VALUES ('a@b.com');

-- SQL Server
IF NOT EXISTS (SELECT 1 FROM users WHERE email = 'a@b.com')
  INSERT INTO users (email) VALUES ('a@b.com');

-- BigQuery (MERGE)
MERGE users AS target
USING (SELECT 'a@b.com' AS email) AS source
ON target.email = source.email
WHEN NOT MATCHED THEN INSERT (email) VALUES (source.email);

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LIMIT and Pagination

-- MySQL + PostgreSQL + SQLite + BigQuery
SELECT * FROM users LIMIT 10 OFFSET 20;

-- SQL Server
SELECT TOP 10 * FROM users;

-- SQL Server with offset (2012+)
SELECT * FROM users
ORDER BY id
OFFSET 20 ROWS FETCH NEXT 10 ROWS ONLY;

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String Aggregation

-- MySQL
GROUP_CONCAT(tag ORDER BY tag SEPARATOR ', ')

-- PostgreSQL + BigQuery
STRING_AGG(tag, ', ' ORDER BY tag)

-- SQL Server
STRING_AGG(tag, ', ') WITHIN GROUP (ORDER BY tag)

-- SQLite
GROUP_CONCAT(tag, ', ')

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Case-Insensitive Matching

-- MySQL (utf8 collation is case-insensitive by default)
WHERE name LIKE 'mani%'

-- PostgreSQL
WHERE name ILIKE 'mani%'

-- SQLite (case-insensitive for ASCII only)
WHERE name LIKE 'mani%'

-- SQL Server (depends on collation — usually case-insensitive by default)
WHERE name LIKE 'mani%'

-- BigQuery (case-sensitive by default)
WHERE LOWER(name) LIKE 'mani%'

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Data Types Quick Reference

Concept	MySQL	PostgreSQL	SQLite	SQL Server	BigQuery
Integer	INT	INT	INTEGER	INT	INT64
Large text	TEXT	TEXT	TEXT	NVARCHAR(MAX)	STRING
Variable string	VARCHAR(n)	VARCHAR(n)	TEXT	NVARCHAR(n)	STRING
Decimal	DECIMAL(p,s)	NUMERIC(p,s)	REAL	DECIMAL(p,s)	NUMERIC
Date and time	DATETIME	TIMESTAMP	TEXT	DATETIME	TIMESTAMP
UUID	VARCHAR(36)	UUID	TEXT	UNIQUEIDENTIFIER	STRING

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