SIZE function in Amazon QLDB
Important
End of support notice: Existing customers will be able to use Amazon QLDB until end of support on 07/31/2025. For more details, see
Migrate an Amazon QLDB Ledger to Amazon Aurora PostgreSQL
In Amazon QLDB, use the SIZE function to return the number of elements in
a given container data type (list, structure, or bag).
Syntax
SIZE (container)
Arguments
container-
The container field name or expression that the function operates on.
Data types
Supported argument types:
-
list
-
structure
-
bag
Return type: int
If the input to SIZE is not a container, the function throws an
error.
Examples
SIZE(`[]`) -- 0 SIZE(`[null]`) -- 1 SIZE(`[1,2,3]`) -- 3 SIZE(<<'foo', 'bar'>>) -- 2 SIZE(`{foo: bar}`) -- 1 (number of key-value pairs) SIZE(`[{foo: 1}, {foo: 2}]`) -- 2 SIZE(12) -- error -- Runnable statements SELECT SIZE(`[]`) FROM << 0 >> -- 0 SELECT SIZE(`[1,2,3]`) FROM << 0 >> -- 3
Related functions
