如果列中存在值，则插入新行

Question

I need to check if a column value exists for a record, and if so insert a duplicate of that record, with one of the fields updated.

The fields for my IncCodes table are are chars:

IncomeCode,
Description,
Location,
CostCentre,
NewIncomeCode

I already have an SQL command which updates all of the IncomeCodes from the NewIncomeCode and clears the NewIncomeCode column where present:

UPDATE IncCodes 
SET IncomeCode = NewIncomeCode
   ,NewIncomeCode = ''
WHERE NewIncomeCode <> ''
  AND Location = Location1

However I need command which does the same thing except instead of updating the IncomeCode field, creates a duplicate record with the IncomeCode updated by the NewIncomeCode field. Something like this pseudo sql:

INSERT INTO IncCodes
VALUES (SELECT NewIncomeCode
              ,Description
              ,Location
              ,CostCentre
              ,NULL
        FROM IncCodes
        WHERE NewIncomeCode <> '')

Any advice much appreciated. I can see similar questions about insert based on criteria but nothing specifically what I need.

Thanks in advance.

Answer 1

INSERT INTO IncCodes (IncomeCode,Description,Location,CostCentre,NewIncomeCode)
SELECT NewIncomeCode
              ,Description
              ,Location
              ,CostCentre
              ,NULL
        FROM IncCodes
        WHERE NewIncomeCode <> ''

Never write an insert without specifying the columsn that is a SQL antipattern and can cause lots of data integrity problems.

Answer 2

INSERT IGNORE INTO IncCodes
    (IncomeCode, Description, Location, CostCentre, NewIncomeCode)
SELECT
    NewIncomeCode, Description, Location, CostCentre, ''
FROM IncCodes
WHERE NewIncomeCode <> '' AND Location = Location1
;