SIZE function in Amazon QLDB - Amazon Quantum Ledger Database (Amazon QLDB)
SyntaxArgumentsData typesExamplesRelated functions

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

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