SQL Server中关键字“选择”附近的语法不正确

Question

I am trying to create a trigger that decreminate the number of books based on the value inserted in the other table. I am using the following code

CREATE TRIGGER updateStock 
ON dbo.command
AFTER INSERT
AS
BEGIN
    UPDATE dbo.book
    SET number = number - (SELECT quant FROM inserted)
    WHERE NLIV = SELECT NLIV FROM inserted 

But I am getting this error:

Incorrect syntax near the keyword 'SELECT'. Incorrect syntax near ')'

Answer 1

That's not the right syntax for an UPDATE if you need to join with another table. Try the following:

CREATE TRIGGER updateStock 
ON dbo.command
AFTER INSERT
AS
BEGIN

UPDATE b
SET b.number = b.number - i.quant
FROM dbo.book b
INNER JOIN INSERTED i
    ON b.NLIV = i.NLIV;

END