Parameters

1. chain_id (uint64, default: 1)
2. token_address (address as hex string, default: 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48)
3. owner (address as hex string, default: 0x48D004a6C175dB331E99BeAf64423b3098357Ae7)
4. spender(address as hex string, default: 0x39AA39c021dfbaE8faC545936693aC917d5E7563)
5. block_number (uint64, default: 0)
   1. Optional. Can be used to view allowances at a particular block. If unset, defaults to 0 and returns latest.

Returns

1. amount (int256 as decimal string)
   1. The amount of the allowance normalized with token_decimals. Note that many contracts treat the max value of uint256 (~1.1579×10^77) as an unlimited allowance that doesn't decrement when the spender uses it.
2. txn_last_changed (address as hex string)
   1. The most recent transaction that impacted the balance.
3. block_last_changed (int64)
   1. The most recent block that impacted the balance.

Query

WITH latest_block_number AS (
  SELECT token_address,
    owner,
    spender,
    MAX(block_number) AS latest_block_number
  FROM @sim.erc20_allowance_changes_block
  WHERE chain_id = $chain_id
    AND token_address = lower($token_address)
    AND owner = lower($owner)
    AND spender = lower($spender)
    AND (
      block_number <= $block_number
      OR $block_number = 0
    )
  GROUP BY token_address,
    owner,
    spender,
    chain_id
)
SELECT (1.0 * a.allowance / POWER(10, a.token_decimals)) AS allowance,
  a.txn_hash as txn_last_changed,
  a.block_number as block_last_changed
FROM @sim.erc20_allowance_changes_block a
  INNER JOIN latest_block_number lbn ON a.block_number = lbn.latest_block_number
WHERE a.token_address = lower($token_address)
  AND a.owner = lower($owner)
  AND a.spender = lower($spender)
  AND a.chain_id = $chain_id