在预期条件的上下文中指定的非布尔类型表达式，靠近“和”。在 CASE 的 SQL Server 中答案

【问题标题】：An expression of non-boolean type specified in a context where a condition is expected, near 'and'. In SQL Server at CASE在预期条件的上下文中指定的非布尔类型表达式，靠近“和”。在 CASE 的 SQL Server 中
【发布时间】：2017-02-04 07:12:16
【问题描述】：

SELECT 
    d.district_id, d.district_name, d1.district_id, d1.district_name
FROM 
    tbl_district d, tbl_district d1 
WHERE
     CASE
        WHEN (d.district_id % 2) != 0 
           THEN d.district_id 
     END
     AND d1.district_id = d.district_id+1;

【问题讨论】：

您需要将case语句的结果与某事进行比较。你的目标到底是什么？
Bad habits to kick : using old-style JOINs - 旧式 逗号分隔的表格列表 样式已替换为 ANSI 中的 proper ANSI JOIN 语法-92 SQL 标准（25 年前），不鼓励使用它

标签： sql-server stored-procedures case where-clause procedure

【解决方案1】：

我猜你正在尝试过滤奇数

SELECT 
    d.district_id, d.district_name, d1.district_id, d1.district_name
FROM 
    tbl_district d 
INNER JOIN tbl_district d1 
        ON d1.district_id = d.district_id+1
WHERE (d.district_id % 2) != 0

也开始使用INNER JOIN，而不是老式的逗号分隔连接

如果你使用SQL SERVER 2012+，那么你可以使用LEAD窗口函数

SELECT *
FROM   (SELECT *,
               Lead(district_id)OVER(ORDER BY district_id) AS next_dst,
               Lead(district_name)OVER(ORDER BY district_id) AS next_name
        FROM   tbl_district ) a
WHERE  a.district_id + 1 = a.next_dst
       AND ( district_id % 2 ) != 0

【讨论】：

【解决方案2】：

“Case when”是一个值，不是逻辑运算。

例如：

 SELECT 
d.district_id, d.district_name, d1.district_id, d1.district_name
FROM 
tbl_district d, tbl_district d1 
WHERE
 CASE
    WHEN (d.district_id % 2) != 0 
       THEN d.district_id 
 END+1 = d1.district_id

【讨论】：

【解决方案3】：

CREATE PROCEDURE [dbo].[EvenOdd_District]
AS
BEGIN

      SELECT d.district_id ,d.district_name,d1.district_id ,d1.district_name
      FROM tbl_district d,tbl_district d1 WHERE d.district_id=
         CASE
            when (d.district_id%2)!=0 then d.district_id 
         END
         AND d1.district_id=d.district_id+1;
END

【讨论】：