我正在尝试在 sql server 中执行合并更新查询。
表“my_table”有 4 列“field”(字符)、“date”(日期)、“val”(数字)、“revision”(日期时间)
查询如下:
MERGE "my_table" AS Target USING ( VALUES ('field_example','2017-01-04','0','2017-01-03 12:02:02')) AS Source ("field","date","val","revision")
ON (Target."field" = Source."field" AND Target."date" = Source."date")
WHEN MATCHED
THEN UPDATE SET Target."val" = Source."val",Target."revision" = Source."revision"
WHEN NOT MATCHED BY TARGET
THEN INSERT ("field","date","val","revision")
VALUES (Source."field", Source."date", Source."val", Source."revision")
OUTPUT $action, Inserted.*, Deleted.*;
由于“my_table”中已经有一行带有 field="field_example"和 date='2017-01-04',我希望此查询更新另外 2 个列“val”、“revision”。
我得到以下查询输出:
$action field date revision val field.1 date.1 revision.1 val.1
1 UPDATE field_example 2017-01-04 2017-01-03 12:02:02 0 field_example 2017-01-04 2017-01-03 10:09:25 161250
所以它看起来不错(应该已经更新了)
但是,当我查看数据库时,该行尚未更新(= val 仍然是 161250 而不是 0,并且修订版仍然是 2017-01-03 10:09:25)
知道为什么吗?
最佳答案
However when I look in the database, the row has not been updated (= val is still 161250 instead of 0, and revision is still 2017-01-03 10:09:25)
Any idea why?
也许您正在查询不同的表/数据库或事务已回滚。下面的脚本按预期工作,猜测实际数据类型。
CREATE TABLE dbo.my_table(
"field" varchar(100)
,"date" date
,"val" int
,"revision" datetime
);
INSERT INTO my_table ("field","date","val","revision")
VALUES ('field_example','2017-01-04','161250','2017-01-03 10:09:25');
MERGE "my_table" AS Target USING ( VALUES ('field_example','2017-01-04','0','2017-01-03 12:02:02')) AS Source ("field","date","val","revision")
ON (Target."field" = Source."field" AND Target."date" = Source."date")
WHEN MATCHED THEN
UPDATE SET Target."val" = Source."val",Target."revision" = Source."revision"
WHEN NOT MATCHED BY TARGET THEN
INSERT ("field","date","val","revision")
VALUES (Source."field", Source."date", Source."val", Source."revision")
OUTPUT $action, Inserted.*, Deleted.*;
SELECT "field","date","val","revision"
FROM my_table;
关于sql - 合并更新查询未按预期执行的问题,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/41436296/