从 PostgresSQL 到 SQL 服务器的带布尔值的大小写表达式

Question

我正在将查询从 PostgreSQL 翻译到 SQL 服务器。我没有在 PostgreSQL 中编写查询，就我的知识而言它非常复杂，所以我不理解它的每一部分。

据我了解：我们试图从 p_policy 中找到最大版本，当 insurancestatus = 7 或 14 / transactiontype = CAN 时，我们比较两个日期（其格式为 BIG INT）。

这是 PG 查询：

SELECT * 
FROM BLABLABLA 
WHERE
pol.vnumber =  (
                  SELECT MAX(pol1.vnumber)
                  FROM p_policy pol1
                  AND ( CASE WHEN   pol1.insurancestatus IN (7,14)  
                                 or pol1.transactiontype IN ('CAN')
                                -- ('CAN','RCA')
                             THEN pol1.veffectivedate = pol1.vexpirydate
                             ELSE pol1.veffectivedate <> pol1.vexpirydate
                             END
                       )
AND pol1.vrecordstatus NOT IN (30,254) 
etc.

我习惯使用 where 语句将它与一个值进行比较。我从 Case 语句中了解到我们将有一个布尔值，但仍然必须与某些东西进行比较？
无论如何，主要目的是让它在 SQL 中工作，但我相信 SQL 无法读取 THEN 比较的 CASE 语句。

这是我试过的：

SELECT * 
FROM BLABLABLA 
WHERE pol.vnumber =  
            (
              SELECT MAX(pol1.vnumber)
              FROM p_policy pol1
            
              WHERE sbuid = 4019
              

              AND ( CASE WHEN   pol1.insurancestatus IN (7,14)  
                             or pol1.transactiontype IN ('CAN')
                         THEN   CASE  
                                    WHEN pol1.veffectivedate = pol1.vexpirydate THEN 1
                                    WHEN pol1.veffectivedate <> pol1.vexpirydate THEN 0
                                 END
                    END
                   )

AND pol1.vrecordstatus NOT IN (30,254) 
etc.

然后我从 SQL 服务器得到这个错误（它直接是当前代码的最后一行 - 所以在双案例语句之后）

Msg 4145, Level 15, State 1, Line 55
An expression of non-boolean type specified in a context where a condition is expected, near 'AND'.

谢谢！有什么不明白的地方请告诉我

Answer 1

我认为您需要布尔逻辑。 CASE 表达式将翻译为：

(
    (
        (pol1.insurancestatus IN (7,14) OR  pol1.transactiontype = 'CAN')
        AND pol1.veffectivedate = pol1.vexpirydate
    ) OR (
        NOT (pol1.insurancestatus IN (7,14) OR pol1.transactiontype = 'CAN')
        AND pol1.veffectivedate <> pol1.vexpirydate
    )
)

Answer 2

您的代码段存在 2 个主要问题，SQL 服务器语法方面。

SELECT * FROM BLABLABLA WHERE 
        pol.vnumber =  /* PROBLEM 1: we haven't defined pol yet; SQL Server has no idea what pol.vnumber is here, so you're going to get an error when you resolve your boolean issue */
        (
          SELECT MAX(pol1.vnumber)
          FROM p_policy pol1
        
          WHERE sbuid = 4019
          

         AND ( CASE WHEN   pol1.insurancestatus IN (7,14)  
                         or pol1.transactiontype IN ('CAN')
                     THEN   CASE  
                                WHEN pol1.veffectivedate = pol1.vexpirydate THEN 1
                                WHEN pol1.veffectivedate <> pol1.vexpirydate THEN 0
                             END
                END
               ) /* PROBLEM 2: Your case statement returns a 1 or a 0.. 
                              which means your WHERE is saying 
                              WHERE sbuid = 4019 
                                AND (1) 
                                AND pol1.vrecordstatus NOT IN (30,254) 

                    SQL Doesn't like that. I think you meant to add a boolean operation using your 1 or 0 after the parenthesis. 
                    like this: */
                = 1

          AND pol1.vrecordstatus NOT IN (30,254)

从 PostgresSQL 到 SQL 服务器的带布尔值的大小写表达式

Case expression with Boolean from PostgreSQL to SQL Server

sql

sql-server

case

where-clause