CASE Statement inside CHECK Constraint Error: An expression of non-boolean type specified in a context where a condition is expected, near ')'

Question

我试图在 SQL 服务器中的 CHECK 约束内使用 CASE 语句，但出现此错误：

Msg 4145, Level 15, State 1, Line 15
An expression of non-boolean type specified in a context where a condition is expected, near ')'.

create table dbo.Advertisement
(
    advertisement_id int NOT NULL PRIMARY KEY,
    roadside_bottom varchar (20),
    roadside_top_bottom varchar (20),
    curbside varchar (20),
    rearside varchar (20),
    headliner varchar(10),
    bus varchar (10),
    CONSTRAINT bottom_pass 
        CHECK(CASE 
                  WHEN roadside_bottom = 'King' AND roadside_top_bottom IS NULL THEN 1 
                  WHEN roadside_bottom = 'Super King' and roadside_top_bottom IS NULL THEN 1 
              END)  
);

我需要语法方面的帮助。

Answer 1

您可以使用 case，但它 returns 是一个值，需要与以下内容进行比较：

CONSTRAINT bottom_pass CHECK
(
    CASE WHEN roadside_bottom = 'King' AND roadside_top_bottom IS NULL THEN 1 
         WHEN roadside_bottom = 'Super King' and roadside_top_bottom IS NULL THEN 1
    END = 1
)

然而，这将更简洁地写成：

CONSTRAINT bottom_pass CHECK
(
    roadside_top_bottom IS NULL AND
    roadside_bottom IN ('King', 'Super King')
)

CASE Statement inside CHECK Constraint Error: An expression of non-boolean type specified in a context where a condition is expected, near ')'

CASE Statement inside CHECK Constraint Error: An expression of non-boolean type specified in a context where a condition is expected, near ')'

sql

tsql

sql-server

constraints