COALESCE

Return the first non-NULL value from a list — the portable way to supply a fallback.

Syntax

COALESCE(value1, value2, ..., valueN)

Parameter	Type	Notes
value1, value2, …*	any	Evaluated left to right. Returns the first one that isn't `NULL`. If every argument is `NULL`, the result is `NULL`.

SQL playground

Loading editor…

⌘/Ctrl + Enter

Arguments don't have to be columns — mix columns, expressions, and a final literal default:

SQL playground

Loading editor…

⌘/Ctrl + Enter

Function	Arguments	Portable?
`COALESCE(a, b, ...)`	any number	yes — standard SQL
`IFNULL(a, b)`	exactly 2	MySQL, SQLite only
`ISNULL(a, b)`	exactly 2	SQL Server only (not the same as Postgres's `ISNULL()`, which doesn't exist there)
`NVL(a, b)`	exactly 2	Oracle only

Prefer COALESCE unless you have a specific reason not to — it works everywhere and isn't capped at two arguments.

All arguments should share a compatible type. Mixing COALESCE(amount, 'N/A') (number, then text) forces a cast and can throw or silently coerce depending on the engine — cast explicitly instead of relying on the mix.
It evaluates every argument up to the first non-NULL one, not lazily skip them entirely — an expensive subquery as an early argument still runs even when a later cheap one would've been the fallback anyway (some engines optimize this, don't rely on it).
COALESCE(x, 0) before dividing is the standard guard against a NULL propagating through arithmetic — but decide if 0 is really the right default, versus excluding the row.

confirm the fallback value makes sense for the column's actual type
verify downstream logic treats the fallback the same as a real value would (or doesn't, if that matters)
check whether a nullable column should stay nullable rather than be normalized away