Eu sei que você não pode comparar um valor com NULL e esperar um resultado sem adicionar algo como no código a seguir ...
SELECT
*
FROM
A INNER JOIN
B ON A.ID = B.ID
WHERE
A.STRING <> B.STRING OR (A.STRING IS NULL AND B.STRING IS NOT NULL) OR (A.STRING IS NOT NULL AND B.STRING IS NULL) OR
A.DT <> B.DT OR (A.DT IS NULL AND B.DT IS NOT NULL) OR (A.DT IS NOT NULL AND B.DT IS NULL) OR
A.B <> B.B OR (A.B IS NULL AND B.B IS NOT NULL) OR (A.B IS NOT NULL AND B.B IS NULL) OR
A.NUM <> B.NUM OR (A.NUM IS NULL AND B.NUM IS NOT NULL) OR (A.NUM IS NOT NULL AND B.NUM IS NULL)
Minha pergunta é:
Existe uma maneira mais elegante de testar os valores alterados nas duas tabelas em que qualquer uma delas pode ser nula?
A solução precisa funcionar de maneira uniforme nos tipos de dados.
Aqui está o código para configurar as tabelas de teste ...
CREATE TABLE A
(
ID INT IDENTITY(1,1) NOT NULL,
STRING VARCHAR(20) NULL,
DT DATETIME NULL,
B BIT NULL,
NUM INT NULL
)
CREATE TABLE B
(
ID INT IDENTITY(1,1) NOT NULL,
STRING VARCHAR(20) NULL,
DT DATETIME NULL,
B BIT NULL,
NUM INT NULL
)
INSERT INTO A (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO A (STRING, DT, B, NUM) VALUES (NULL, '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO A (STRING, DT, B, NUM) VALUES ('TEST', NULL, 0, 23)
INSERT INTO A (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', NULL, 23)
INSERT INTO A (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, NULL)
INSERT INTO A (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO A (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO A (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO A (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO A (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO B (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO B (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO B (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO B (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO B (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO B (STRING, DT, B, NUM) VALUES ('STAGE', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO B (STRING, DT, B, NUM) VALUES ('TEST', '2555-11-11 00:00:00.000', 0, 23)
INSERT INTO B (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO B (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 23)
INSERT INTO B (STRING, DT, B, NUM) VALUES ('TEST', '2012-03-16 16:39:04.893', 0, 999)