There is too much space in the select columns, pushing some parts of the calculations to the right side. It's often too far to support easy calculation readability.
MSSQL, profile used: jr5
SELECT
CtrlRecordId = DataSource.CtrlRecordId
,[AccountName] = 'AMEX'
,TransactionURC = CONVERT(NVARCHAR(MAX), DataSource.[Date], 103) + ' | ' + CONVERT(NVARCHAR(MAX), -1 * DataSource.Amount) + ' | ' + DataSource.Reference
,TransactionOperation = IIF((-1 * DataSource.Amount) >= 0 , 'CREDIT', 'DEBIT')
,TransactionDate = DataSource.[Date]
,TransactionTime = CONVERT(TIME, NULL)
,AmountOnAccount = -1 * DataSource.Amount
,LocalAmount = -1 * DataSource.Amount
,LocalCurrencyCode = 'GBP'
,TransactionType = DataSource.Category
,Description1 = DataSource.AppearsOnYourStatementAs
,Description2 = DataSource.[Description]
,Description3 = DataSource.ExtendedDetails
,UserComment = NULL
FROM StageTyped.AMEXBA_0001__StatementLong DataSource
WHERE DataSource.CtrlCargoRecordValidityFlagId < 100
AND DataSource.CtrlETLStatusFlagId = 1
/*-----------------------------------------------------------------------------------------------------------------------------
--expected behaviour:
SELECT
CtrlRecordId = DataSource.CtrlRecordId
,[AccountName] = 'AMEX'
,TransactionURC = CONVERT(NVARCHAR(MAX), DataSource.[Date], 103) + ' | ' + CONVERT(NVARCHAR(MAX), -1 * DataSource.Amount) + ' | ' + DataSource.Reference
,TransactionOperation = IIF((-1 * DataSource.Amount) >= 0 , 'CREDIT', 'DEBIT')
,TransactionDate = DataSource.[Date]
,TransactionTime = CONVERT(TIME, NULL)
,AmountOnAccount = -1 * DataSource.Amount
,LocalAmount = -1 * DataSource.Amount
,LocalCurrencyCode = 'GBP'
,TransactionType = DataSource.Category
,Description1 = DataSource.AppearsOnYourStatementAs
,Description2 = DataSource.[Description]
,Description3 = DataSource.ExtendedDetails
,UserComment = NULL
FROM StageTyped.AMEXBA_0001__StatementLong DataSource
WHERE DataSource.CtrlCargoRecordValidityFlagId < 100
AND DataSource.CtrlETLStatusFlagId = 1
-----------------------------------------------------------------------------------------------------------------------------*/