check-constraints

I am trying to create a table where the values in one column can't be greater than the next column over. For example, I am creating the following table. CREATE TABLE Price ( PriceID INT PRIMARY KEY IDENTITY (1,1), OriginalPrice FLOAT NOT NULL, CurrentPrice FLOAT NOT NULL, Discount FLOAT, ShippingCost FLOAT NOT NULL, Tax FLOAT NOT NULL); And Current Price cannot be greater than OriginalPrice. So what I tried doing was CurrentPrice FLOAT CHECK (CurrentPrice <= OriginalPrice) NOT NULL, But this gives me the following error: Msg 8141, Level 16, State 0, Line 1 Column CHECK constraint for column

I have the following tables in a SQL Server 2008 db: tblItem , which has an ItemID field; tblGoodItem , which also has an ItemID field, and has a foreign key pointing to tblItem; tblBadItem , which also has an ItemID field, and also has a foreign key pointing to tblItem. An item cannot be both a good item and a bad item; it must either be the one or the other. However, whether the item is good or bad, it must be an item. My question is this: how do I add a constraint to the ItemID fields in both tblGoodItem and tblBadItem so that an ItemID value cannot exist in both tables ? I've read some

This question already has an answer here: CHECK constraint in MySQL is not working 8 answers I have created a table schedule with a check constraint: mysql> create table schedule(order_date date, dely_date date check(dely_date>order_date)); Query OK, 0 rows affected (0.50 sec) When I insert a value which violates check constraint, sql reports no error. mysql> insert into schedule values('2015-11-20','2014-12-25'); Query OK, 1 row affected (0.10 sec) mysql> select * from schedule; +------------+------------+ | order_date | dely_date | +------------+------------+ | 2015-11-20 | 2014-12-25 | +---

Constraint for phone number to be of 7 digits. How to check if it is of 7 digits in SQL Server? CREATE TABLE Customer ( C_ID INT NOT NULL IDENTITY(1,1) PRIMARY KEY, C_Name VARCHAR(255) NOT NULL, Phone INT ); Do not store phone numbers as integers. Some valid numbers, for instance, could start with a 0 -- if not today, perhaps in the future. To do the validation check, you can use like : CREATE TABLE Customer ( C_ID INT NOT NULL IDENTITY(1, 1) PRIMARY KEY, C_Name VARCHAR(255) NOT NULL, Phone CHAR(7), -- you might not want to have such a precise length CONSTRAINT chk_phone CHECK (phone not like