在book表中,将工具书类型(tool)的书的书架序号都减少2,下列语句正确的是()
在book表中,将工具书类型(tool)的书的书架序号都减少2,下列语句正确的是()
UPDATE books SET shelf = shelf - 2 WHERE type IS 'tool';
INSERT books SET shelf = shelf - 2 WHERE type IS 'tool';
UPDATE books SET shelf = shelf - 2 WHERE type = 'tool';
UPDATE books INTO shelf = shelf - 2 WHERE type = 'tool';