An UPDATE statement can only modify data of a single table : Update « Insert Delete Update « SQL Server / T-SQL






An UPDATE statement can only modify data of a single table

1> CREATE TABLE works_on        (emp_no       INTEGER NOT NULL,
2>                         project_no    CHAR(4) NOT NULL,
3>                         job CHAR (15) NULL,
4>                         enter_date    DATETIME NULL)
5>
6> insert into works_on values (1, 'p1', 'analyst', '1997.10.1')
7> insert into works_on values (1, 'p3', 'manager', '1999.1.1')
8> insert into works_on values (2, 'p2', 'clerk',   '1998.2.15')
9> insert into works_on values (2, 'p2',  NULL,     '1998.6.1')
10> insert into works_on values (3, 'p2',  NULL,     '1997.12.15')
11> insert into works_on values (4, 'p3', 'analyst', '1998.10.15')
12> insert into works_on values (5, 'p1', 'manager', '1998.4.15')
13> insert into works_on values (6, 'p1',  NULL,     '1998.8.1')
14> insert into works_on values (7, 'p2', 'clerk',   '1999.2.1')
15> insert into works_on values (8, 'p3', 'clerk',   '1997.11.15')
16> insert into works_on values (7, 'p1', 'clerk',   '1998.1.4')
17>
18> select * from works_on
19> GO

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)
emp_no      project_no job             enter_date
----------- ---------- --------------- -----------------------
          1 p1         analyst         1997-10-01 00:00:00.000
          1 p3         manager         1999-01-01 00:00:00.000
          2 p2         clerk           1998-02-15 00:00:00.000
          2 p2         NULL            1998-06-01 00:00:00.000
          3 p2         NULL            1997-12-15 00:00:00.000
          4 p3         analyst         1998-10-15 00:00:00.000
          5 p1         manager         1998-04-15 00:00:00.000
          6 p1         NULL            1998-08-01 00:00:00.000
          7 p2         clerk           1999-02-01 00:00:00.000
          8 p3         clerk           1997-11-15 00:00:00.000
          7 p1         clerk           1998-01-04 00:00:00.000

(11 rows affected)
1>
2> -- An UPDATE statement can only modify data of a single table.
3>
4>
5> UPDATE works_on
6>         SET job = 'Manager'
7>         WHERE emp_no = 2
8>         AND project_no = 'p2'
9> GO

(2 rows affected)
1> select * from works_on
2> GO
emp_no      project_no job             enter_date
----------- ---------- --------------- -----------------------
          1 p1         analyst         1997-10-01 00:00:00.000
          1 p3         manager         1999-01-01 00:00:00.000
          2 p2         Manager         1998-02-15 00:00:00.000
          2 p2         Manager         1998-06-01 00:00:00.000
          3 p2         NULL            1997-12-15 00:00:00.000
          4 p3         analyst         1998-10-15 00:00:00.000
          5 p1         manager         1998-04-15 00:00:00.000
          6 p1         NULL            1998-08-01 00:00:00.000
          7 p2         clerk           1999-02-01 00:00:00.000
          8 p3         clerk           1997-11-15 00:00:00.000
          7 p1         clerk           1998-01-04 00:00:00.000

(11 rows affected)
1> drop table works_on
2> GO
1>

           
       








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