sql - SQL中如何将外键设为NULLABLE？

Question

    CREATE TABLE [M].[SocialInfo]
    (
        [Id] UNIQUEIDENTIFIER NOT NULL PRIMARY KEY DEFAULT newid(), 
[MemberId] UNIQUEIDENTIFIER  DEFAULT newid(),
    [GroupId] UNIQUEIDENTIFIER  DEFAULT newid(),
        [NewsURL] VARCHAR(200) NULL,     
        CONSTRAINT [FK_SocialInfo_Member] FOREIGN KEY ([MemberId]) REFERENCES [M].[Member]([Id]), 
        CONSTRAINT [FK_SocialInfo_Group] FOREIGN KEY ([GroupId]) REFERENCES [M].[Group]([Id]) 
    )

How can I make both FK nullable?

I'm unable to get the syntax?

Answer 1

我认为您刚刚遗漏了专栏创建部分。

CREATE TABLE [M].[SocialInfo]
(
    [Id] UNIQUEIDENTIFIER NOT NULL PRIMARY KEY DEFAULT newid(), 
    [NewsURL] VARCHAR(200) NULL,     
    MemberId INT NULL,
    GroupId INT NULL,
    CONSTRAINT [FK_SocialInfo_Member] FOREIGN KEY ([MemberId]) REFERENCES [M].[Member]([Id]), 
    CONSTRAINT [FK_SocialInfo_Group] FOREIGN KEY ([GroupId]) REFERENCES [M].[Group]([Id]) 
)