SQL Server 2022

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CREATE TABLE dbo.T (i integer PRIMARY KEY);
INSERT dbo.T (i) VALUES (2), (3), (4);
CREATE TABLE dbo.TT (q sql_variant NULL);
3 rows affected

UPDATE T
SET T.i = 1
FROM dbo.TT AS TT;
SELECT * FROM dbo.T;


i


2

3

4


INSERT dbo.TT (q) DEFAULT VALUES;
1 rows affected

UPDATE T
SET T.i = 1
FROM dbo.TT AS TT;
Msg 2627 Level 14 State 1 Line 1
Violation of PRIMARY KEY constraint 'PK__T__3BD01996D971A625'. Cannot insert duplicate key in object 'dbo.T'. The duplicate key value is (1).
Msg 3621 Level 0 State 0 Line 1
The statement has been terminated.

SELECT * FROM dbo.T;


i


2

3

4