GREATEST in PostgreSQL - Examples & AI Generator

When you want to find the largest value among several columns or expressions in PostgreSQL, the GREATEST function is your go-to tool. But remembering the exact PostgreSQL GREATEST syntax—or switching between different SQL dialects—can slow you down.
AI2sql offers an instant solution: just type your request in plain English and get production-ready queries in seconds—no manual coding, no memorization.

GREATEST Syntax in PostgreSQL

Standard Usage

The PostgreSQL GREATEST function returns the largest value from a list of expressions. Its syntax:

GREATEST(value1, value2, ...)

• Accepts two or more arguments.

• Arguments must be of comparable types (e.g., numbers, same text type).

• If any argument is NULL, the result is NULL.

GREATEST Examples You Can Generate Instantly

Instead of memorizing variations of GREATEST PostgreSQL syntax, see below for real-world usage. All examples are copy-paste ready:

1. Highest Sales Amount Per Customer

SELECT customer_id, GREATEST(online_sales, store_sales, phone_sales) AS max_sales
FROM customers;

2. Latest Delivery Date Among Three Possible Dates

SELECT order_id, GREATEST(order_date, shipped_date, delivered_date) AS most_recent_event
FROM orders;

3. Highest Product Rating (Multiple Review Sources)

SELECT product_id, GREATEST(expert_rating, user_rating, vendor_rating) AS top_rating
FROM products;

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Why Use AI2sql Instead of Manual GREATEST Coding

• Skip documentation: Get correct PostgreSQL GREATEST syntax instantly.

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• Supports 80+ countries: Trusted by 50,000+ users—AI2sql adapts to all major SQL dialects.

Try AI2sql Generator – or Learn GREATEST for more technical deep-dives.

Conclusion

The GREATEST function in PostgreSQL is essential for comparing multiple values in one row. But manual coding across varying SQL dialects is time-consuming, even for seasoned developers or analysts. AI2sql removes the guesswork, giving you optimized GREATEST queries in seconds—no coding, zero errors, ready for business uses.

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