Updating multiple columns camazon dating
Each assignment specifies a column name on the left side the assignment operator (=) and a literal value, an expression, or data from a subquery on the right side of the assignment operator.Third, the WHERE clause specifies the rows that you want to update. The WHERE clause specifies which record(s) that should be updated.It is safe or there is a chance that the columns are update with different time, beacause of the 2 visible calls to now() ?
I have no problem in doing this but it looks so mean the way you said. This book includes scripts and tools to hypercharge Oracle 11g performance and you can buy it for 30% off directly from the publisher.UPDATE summary_data SET current_category = (SELECT category_id FROM products WHERE products.product_id = summary_data.product_id) WHERE EXISTS (SELECT category_id FROM products WHERE products.product_id = summary_data.product_id); If you want to test your skills using the SQL UPDATE statement, try some of our practice exercises.I don't think that it can be update with different values (I think internaly mysql calls now() just once per row or something similar) , but I'm not an expert, what do you think ?Second question why this query doesn't update the columns: the following statement sets col2 to the current (updated) col1 value, not the original col1 value.