我知道你不能将一个值与 NULL 进行比较并期望得到一个结果而不添加类似以下代码的内容......

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) 

我的问题是：

是否有更优雅的方法来测试两个表中任何一个可能为空的值的更改？

解决方案需要跨数据类型统一工作。

这是设置测试表的代码......

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)