sql - 变量名称在查询批处理或存储过程中必须是唯一的吗？

Question

我们如何在一个事务中运行多个 SQL 脚本，其中每个脚本可能定义相同的变量？

文件1:

declare @tableName varchar(28), @query nvarchar(1000)
set @tableName = '1apples'+convert(varchar(28), getdate(),121)
select @query = 'select name into ' + quotename(@tableName) + ' from sys.objects'
print @query
exec (@query)
go

文件2:

declare @tableName varchar(28), @query nvarchar(1000)
set @tableName = '2apples'+convert(varchar(28), getdate(),121)
select @query = 'select name into ' + quotename(@tableName) + ' from sys.objects'
print @query
exec (@query)
 go

我正在 PowerShell 中执行这样的文件:

try {

  $files = Get-ChildItem -Path $SqlFilesDirectory -File -Filter *.sql
  $filesSorted = $files |Sort-Object -Property Name
  $filesconcatenated = @(
      $files |Get-Content -Raw
  ) -join [Environment]::NewLine
  $filesconcatenated = 'SET XACT_ABORT ON ' + $filesconcatenated + ' SET XACT_ABORT OFF ' + [Environment]::NewLine
    $cmd = New-Object System.Data.SqlClient.SqlCommand ($filesconcatenated), $conn
    $cmd.Transaction = $tran
    [void]$cmd.ExecuteNonQuery()
   
  $tran.Commit()
}
catch {
  $tran.Rollback()
  Write-Host "Record not Inserted ->"
  $_.exception.message
}
finally {
  $conn.Close()
}

我遇到以下异常:

Exception calling "ExecuteNonQuery" with "0" argument(s): "Incorrect syntax near the keyword 'declare'. The variable name '@tableName' has already been declared. Variable names must be unique within a query batch or stored procedure. The variable name '@tableName' has already been declared. Variable names must be unique within a query batch or stored procedure. Incorrect syntax near the keyword 'SET'."

我们如何在一个事务中运行多个 SQL 脚本，其中每个脚本可能定义相同的变量？

这是它尝试运行的完整脚本:

SET XACT_ABORT ON 
declare @tableName varchar(28), @query nvarchar(1000)
set @tableName = '1apples'+convert(varchar(28), getdate(),121)
select @query = 'select name into ' + quotename(@tableName) + ' from sys.objects'
print @query
exec (@query)
go
declare @tableName varchar(28), @query nvarchar(1000)
set @tableName = '2apples'+convert(varchar(28), getdate(),121)
select @query = 'select name into ' + quotename(@tableName) + ' from sys.objects'
print @query
exec (@query)
go
declare @tableName varchar(28), @query nvarchar(1000)
set @tableName = '3apples'+convert(varchar(28), getdate(),121)
select @query = 'select name into ' + quotename(@tableName) + ' from sys.objects'
print @query
exec (@query)
go
 SET XACT_ABORT OFF 

Answer 1

在一个批处理中不能两次使用相同的变量

因此，通过循环数组将它们作为单独的命令执行

$connString = "Server=tcp:$ServerName.database.windows.net,1433;Database=$DBName;User Id=$SvcAdminAccount@$ServerName;Password=$SvcAdminPassword;MultipleActiveResultSets=true;Persist Security Info=true;";
$conn = New-Object System.Data.SqlClient.SqlConnection $connString try
{
  $conn.Open()
  $files = Get-ChildItem -Path $SqlFilesDirectory -File -Filter *.sql
  $filesSorted = $files |Sort-Object -Property Name
  $tran = $conn.BeginTransaction()
  foreach ($file in $filesSorted)
  {
    $query = "SET XACT_ABORT ON; " + (Get-Content -Raw $file)
    $cmd = New-Object System.Data.SqlClient.SqlCommand ($query, $conn, $tran)
    [void]$cmd.ExecuteNonQuery()
  }
  $tran.Commit();
}
catch {
  Write-Host "Record not Inserted ->"
  $_.exception.message
}
finally {
  $tran.Dispose()
  $conn.Dispose()
}

Note the way Dispose is used, rather than Rollback, because Dispose will never throw an exception. It's also in the finally rather than the catch