Ambiguous column name during table join : Table alias « Table « SQL Server / T-SQL Tutorial

1. SQL Server / T-SQL Tutorial
2. Table
3. Table alias

4>
5>
6> create table Billings (
7>     BankerID           INTEGER,
8>      BillingNumber      INTEGER,
9>      BillingDate        datetime,
10>      BillingTotal       INTEGER,
11>      TermsID            INTEGER,
12>      BillingDueDate     datetime ,
13>      PaymentTotal       INTEGER,
14>      CreditTotal        INTEGER
15>
16>  );
17>  GO
1>
2> INSERT INTO Billings VALUES (1, 1, '2005-01-22', 165, 1,'2005-04-22',123,321);
3> GO

(1 rows affected)
1>
2>
3> INSERT INTO Billings VALUES (2, 2, '2001-02-21', 165, 1,'2002-02-22',123,321);
4> GO

(1 rows affected)
1>
2>
3> INSERT INTO Billings VALUES (3, 3, '2003-05-02', 165, 1,'2005-04-12',123,321);
4> GO

(1 rows affected)
1>
2>
3> INSERT INTO Billings VALUES (4, 4, '1999-03-12', 165, 1,'2005-04-18',123,321);
4> GO

(1 rows affected)
1>
2>
3> INSERT INTO Billings VALUES (5, 5, '2000-04-23', 165, 1,'2005-04-17',123,321);
4> GO

(1 rows affected)
1>
2>
3> INSERT INTO Billings VALUES (6, 6, '2001-06-14', 165, 1,'2005-04-18',123,321);
4> GO

(1 rows affected)
1>
2>
3> INSERT INTO Billings VALUES (7, 7, '2002-07-15', 165, 1,'2005-04-19',123,321);
4> GO

(1 rows affected)
1>
2>
3> INSERT INTO Billings VALUES (8, 8, '2003-08-16', 165, 1,'2005-04-20',123,321);
4> GO

(1 rows affected)
1>
2>
3> INSERT INTO Billings VALUES (9, 9, '2004-09-17', 165, 1,'2005-04-21',123,321);
4> GO

(1 rows affected)
1>
2>
3> INSERT INTO Billings VALUES (0, 0, '2005-10-18', 165, 1,'2005-04-22',123,321);
4> GO

(1 rows affected)
1>
2>
3>
4> UPDATE Billings
5> SET CreditTotal = CreditTotal + 100
6> FROM(SELECT TOP 5 * FROM Billings) AS TopBillings
7>
8>  GO
Msg 209, Level 16, State 1, Server J\SQLEXPRESS, Line 5
Ambiguous column name 'CreditTotal'.
1>
2>
3> drop table Billings;
4> GO