SQL server 2012 tables issue, sysdate and to_date issue - sql

Question

I have two issues while trying to create tables.
For **sysdate*** it says invalid column name
for *TO_DATE('01-JAN-2008','DD-MON-YYYY')));* it says TO_DATE is not a reconigized built-in function name.
^ both are in the Table Invoice.
This is using SQL SERVER 2012
CREATE TABLE VENDOR(
V_CODE INTEGER NOT NULL UNIQUE,
V_NAME VARCHAR(35) NOT NULL,
V_CONTACT VARCHAR(15) NOT NULL,
V_AREACODE CHAR(3) NOT NULL,
V_PHONE CHAR(8) NOT NULL,
V_STATE CHAR(2) NOT NULL,
v_ORDER CHAR(1) NOT NULL,
PRIMARY KEY (V_CODE));
CREATE TABLE PRODUCT(
P_CODE VARCHAR(10) NOT NULL,
P_DESCRIPT VARCHAR(35) NOT NULL,
P_INDATE DATE NOT NULL,
P_QOH SMALLINT NOT NULL,
P_MIN SMALLINT NOT NULL,
P_PRICE DECIMAL(8,2) NOT NULL,
P_DISCOUNT DECIMAL(5,2) NOT NULL,
V_CODE INTEGER,
PRIMARY KEY (P_CODE),
FOREIGN KEY(V_CODE) REFERENCES VENDOR ON UPDATE CASCADE);
CREATE TABLE CUSTOMER(
CUS_CODE DECIMAL PRIMARY KEY,
CUS_LNAME VARCHAR(15) NOT NULL,
CUS_FNAME VARCHAR(15) NOT NULL,
CUS_INITIAL CHAR(1),
CUS_AREACODE CHAR(3) DEFAULT '615' NOT NULL,
CHECK(CUS_AREACODE IN ('615','713','931')),
CUS_PHONE CHAR(8) NOT NULL,
CUS_BALANCE DECIMAL(9,2) DEFAULT 0.00,
CONSTRAINT CUS_UI1 UNIQUE (CUS_LNAME, CUS_FNAME));
CREATE TABLE INVOICE (
INV_NUMBER DECIMAL PRIMARY KEY,
CUS_CODE DECIMAL NOT NULL REFERENCES CUSTOMER(CUS_CODE),
INV_DATE DATE DEFAULT SYSDATE NOT NULL,
CONSTRAINT INV_CK1 CHECK (INV_DATE > TO_DATE('01-JAN-2008','DD-MON-YYYY')));

Answer 1

You have two issues:
the function to get the current system date and time is called SYSDATETIME() in T-SQL/SQL Server (not sysdate)
the way to convert a string to a date or datetime in T-SQL/SQL Server is using CAST or CONVERT (not TO_DATE - there is no such function in T-SQL)
Use something like
SELECT CAST('01-JAN-2008' AS DATE)
or something like that (it's highly dependent on your language/date format settings in SQL Server whether it'll work or not). If you need to specify a specific format, you can use CONVERT which allows you to use one of the many predefined formats (see relevant details in the MSDN documentation).
If that's still not enough - SQL Server 2012 has a new function called PARSE which allows you to specify any arbitrary date format that your string is formatted in. Again, see the relevant MSDN documentation for details.
The best thing is to avoid converting dates back and forth to and from strings if ever possible, and in your case, this should be easily doable! Just use:
INV_DATE DATE DEFAULT SYSDATETIME() NOT NULL,
CONSTRAINT INV_CK1 CHECK (INV_DATE > '20080101');