sql-server - 在 SQL Server 中将数据插入到表的列中

Question

我有一个有 2 列的表：SolarDate,GregorianDate

我有一个在 T-SQL 中将公历日期转换为太阳日期的函数。当一行插入到这个表中时，它只会填充GregorianDate列。

我想在插入一行时，SolarDate也填充字段。

我需要触发吗？还是别的东西？

我该怎么做？

Answer 1

You could use a trigger - or just define your SolarDate as a computed column based on that function that you have.

In that case - you need to first remove that column SolarDate that you already have, and then add it again as a computed column:

ALTER TABLE dbo.YourTable
ADD SolarDate AS dbo.DetermineSolarDate(GregorianDate)

This would constantly and automatically determine the SolarDate whenever you need that value, and you don't need to have a trigger in place for this to work.

Answer 2

您可以在使用 UDF 的表上创建计算列。

CREATE FUNCTION ArbSQ
(
    @Num1 INT
)
RETURNS INT
AS
BEGIN

    RETURN POWER(@Num1, 2)

END
GO

CREATE TABLE MyTable
(
    MyNum INT
    ,MySQ AS dbo.ArbSQ(MyNum) 
)

INSERT INTO MyTable
VALUES (1), (2), (3)

SELECT *
FROM MyTable

在此示例中（不再使用标量 UDF），计算列可以是PERSISTED；

CREATE TABLE MyTable
(
    MyNum INT
    ,MySQ AS POWER(MyNum, 2) PERSISTED
)

INSERT INTO MyTable
VALUES (1), (2), (3)

SELECT *
FROM MyTable