Опитайте този тригер (той ще копира стойностите от ColumnB в ColumnA, когато се вмъкнат стойности в ColumnB или когато се актуализират стойностите от ColumbB):
CREATE TRIGGER trgIU_triggertestTable_UpdateColumnAWhenColumnB
ON dbo.triggertestTable
AFTER INSERT,UPDATE
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
IF UPDATE(ColumnB)
BEGIN
UPDATE dbo.triggertestTable
SET ColumnA=i.ColumnB
FROM inserted i
INNER JOIN dbo.triggertestTable t ON i.MyID=t.MyID
LEFT JOIN deleted d ON i.MyID=d.MyID
WHERE d.MyID IS NULL AND i.ColumnB IS NOT NULL -- Row was inserted
OR d.MyID IS NOT NULL -- Row was updated
END
END
GO
Използвах тази таблица:
CREATE TABLE dbo.triggertestTable(
MyID INT IDENTITY(1,1) PRIMARY KEY, -- MyID should be a PRIMARY KEY or a mandatory(NOT NULL) UNIQUE constraint
ColumnA VARCHAR(100),
ColumnB VARCHAR(100)
);
GO