This can be used from the sqlite backend.
SELECT accounts.name AS Ledger, transactions.description AS Record,
CAST(splits.value_num AS FLOAT)/splits.value_denom AS Amount
FROM accounts
LEFT JOIN splits ON accounts.guid=splits.account_guid
LEFT JOIN transactions ON splits.tx_guid=transactions.guid
WHERE placeholder=1 AND splits.guid notnull
SELECT * FROM splits WHERE account_guid='<FROM>'
SELECT * FROM splits WHERE tx_guid IN (
SELECT tx_guid FROM splits
WHERE account_guid='<FROM>'
)
SELECT * FROM splits S
WHERE account_guid='<FROM>'
AND EXISTS (
SELECT NULL FROM splits T
WHERE T.tx_guid = S.tx_guid
AND account_guid='<JUMP>'
)
UPDATE splits SET account_guid='<TO>'
WHERE guid IN (
SELECT guid FROM splits S
WHERE account_guid='<FROM>'
AND EXISTS (
SELECT NULL FROM splits T
WHERE T.tx_guid = S.tx_guid
AND account_guid='<JUMP>'
)
)