Question

我有一个简单的SQL Server表，用于与两个数字列的多对多关联

PFM_USER_ID
ACCOUNT_ID

我们计划删除多对多，并在Account指向PFM_USER时创建一个外键，并根据需要复制Account条记录（及其子代）。

在计划删除此表时，我编写了以下内容并在Squirrel中运行它，期望BREAK导致循环结束。目的只是为了确保我要开发的逻辑能够正确地运行。

DECLARE @LastUserId INT
DECLARE @CurrentUserId INT
DECLARE @CurrentAccountId INT
DECLARE @Counter int
SET @LastUserId = 0
SET @Counter = 0

DECLARE UsersAndAccounts CURSOR LOCAL FOR 
SELECT * FROM PFM_USER_ACCOUNT ORDER BY  ACCOUNT_ID asc, PFM_USER_ID asc

OPEN UsersAndAccounts

FETCH NEXT FROM UsersAndAccounts into @CurrentUserId, @CurrentAccountId
WHILE @@FETCH_STATUS = 0 
BEGIN
     SET @Counter += 1
     IF  @Counter > 10
        BREAK 
    PRINT N'Examining Count ' + CAST(@Counter AS varchar ) + ' for USER '
       + CAST(@CurrentUserId AS varchar ) + ' and Account ' 
       + CAST(@CurrentAccountId AS varchar )
    -- A lot of logic, inserting new Accont records, copied from the existing one, goes here
    -- Many intended details omitted.
FETCH NEXT FROM UsersAndAccounts into @CurrentUserId, @CurrentAccountId
END

CLOSE UsersAndAccounts
DEALLOCATE UsersAndAccounts

我期望输出像（...表示我没有捕获的数字 - 值无关紧要）：

Examining Count 1 for USER ... and Account ...
Examining Count 2 for USER ... and Account ...
Examining Count 3 for USER ... and Account ...
Examining Count 4 for USER ... and Account ...
Examining Count 5 for USER ... and Account ...
Examining Count 6 for USER ... and Account ...
Examining Count 7 for USER ... and Account ...
Examining Count 8 for USER 82 and Account 620
Examining Count 9 for USER 85 and Account 629
Examining Count 10 for USER 85 and Account 631

相反，我得到的输出看起来好像有两个@Counter变量和一个内部循环，就好像它一样（因为我对Java更熟悉）

for( int count1 = 0; count1 < 10; count1++) {
    for( int count2 = count1; count2 < 10; count2) {
        System.out.println("Examining count " + count2 + " [plus other stuff]");
    }
}

Squirrel控制台也报告警告我没有找到任何有用的信息。说明事情的输出的最后一点是：

Warning:   Examining Count 8 for USER 82 and Account 620
SQLState:  S0001
ErrorCode: 0Warning:   Examining Count 9 for USER 85 and Account 629
SQLState:  S0001
ErrorCode: 0Warning:   Examining Count 10 for USER 85 and Account 631
SQLState:  S0001
ErrorCode: 0
Warning:   Examining Count 9 for USER 85 and Account 629
SQLState:  S0001
ErrorCode: 0Warning:   Examining Count 10 for USER 85 and Account 631
SQLState:  S0001
ErrorCode: 0
Warning:   Examining Count 10 for USER 85 and Account 631
SQLState:  S0001
ErrorCode: 0

我尝试在循环内删除了测试/ BREAK并更改了WHILE以进行测试，结果相似。

选择前10名并完全忽略@Counter也是如此

请解释我做错了什么，或者我怎么误解了这里发生的事情

谢谢，乔治麦金尼

Answer 1

请尝试以下方法：

select 
      'Examining Count ' + ROW_NUMBER() 
    + '; USER ' + CAST(@CurrentUserId AS varchar ) 
    + ' and Account ' + CAST(@CurrentAccountId AS varchar )
from PFM_USER_ACCOUNT 
ORDER BY
    ACCOUNT_ID asc
   ,PFM_USER_ID asc

SQL Server while循环似乎嵌套调用

1 个答案: