SQL Server – Retrieve Logical Filename from Backup File

I wrote a blog post at SQLServerScience.com that shows how to obtain the details you're after, and is compatible with all versions of SQL Server since 2008+

This is the main code from that blog post:

/*
    This script will generate a "RESTORE DATABASE" command with the correct "MOVE" clause, etc.

    By: Max Vernon
*/

SET NOCOUNT ON;
DECLARE @FileListCmd            nvarchar(max);
DECLARE @RestoreCmd             nvarchar(max);
DECLARE @cmd                    nvarchar(max);
DECLARE @BackupFile             nvarchar(max);
DECLARE @DBName                 sysname;
DECLARE @DataPath               nvarchar(260);
DECLARE @LogPath                nvarchar(260);
DECLARE @Version                decimal(10,2);
DECLARE @MaxLogicalNameLength   int;
DECLARE @MoveFiles              nvarchar(max);

SET @BackupFile     = N'D:\SQLServer\MyDatabaseBackup.bak'; --source backup file
SET @DBName         = N'MyDB'; --target database name
SET @DataPath       = N'C:\Database\Data'; --target data path
SET @LogPath        = N'C:\Database\Log'; --target log path

/* ************************************

    modify nothing below this point.

   ************************************ */
IF RIGHT(@DataPath, 1) <> '\' SET @DataPath = @DataPath + N'\';
IF RIGHT(@LogPath, 1) <> '\' SET @LogPath = @LogPath + N'\';
SET @cmd = N'';
SET @Version = CONVERT(decimal(10,2), 
    CONVERT(varchar(10), SERVERPROPERTY('ProductMajorVersion')) 
    + '.' + 
    CONVERT(varchar(10), SERVERPROPERTY('ProductMinorVersion'))
    );
IF @Version IS NULL --use ProductVersion instead
BEGIN
    DECLARE @sv varchar(10);
    SET @sv = CONVERT(varchar(10), SERVERPROPERTY('ProductVersion'));
    SET @Version = CONVERT(decimal(10,2), LEFT(@sv, CHARINDEX(N'.', @sv) + 1));
END

IF OBJECT_ID(N'tempdb..#FileList', N'U') IS NOT NULL
BEGIN
    DROP TABLE #FileList;
END
CREATE TABLE #FileList 
(
      LogicalName               sysname             NOT NULL
    , PhysicalName              varchar(255)        NOT NULL
    , [Type]                    char(1)             NOT NULL
    , FileGroupName             sysname             NULL
    , Size                      numeric(20,0)       NOT NULL
    , MaxSize                   numeric(20,0)       NOT NULL
    , FileId                    bigint              NOT NULL
    , CreateLSN                 numeric(25,0)       NOT NULL
    , DropLSN                   numeric(25,0)       NULL
    , UniqueId                  uniqueidentifier    NOT NULL
    , ReadOnlyLSN               numeric(25,0)       NULL
    , ReadWriteLSN              numeric(25,0)       NULL
    , BackupSizeInBytes         bigint              NOT NULL
    , SourceBlockSize           int                 NOT NULL
    , FileGroupId               int                 NULL
    , LogGroupGUID              uniqueidentifier    NULL
    , DifferentialBaseLSN       numeric(25,0)       NULL
    , DifferentialBaseGUID      uniqueidentifier    NOT NULL
    , IsReadOnly                bit                 NOT NULL
    , IsPresent                 bit                 NOT NULL 
);

IF @Version >= 10.5 ALTER TABLE #FileList ADD TDEThumbprint varbinary(32) NULL;
IF @Version >= 12   ALTER TABLE #FileList ADD SnapshotURL nvarchar(360) NULL;

SET @FileListCmd = N'RESTORE FILELISTONLY FROM DISK = N''' + @BackupFile + N''';';

INSERT INTO #FileList
EXEC (@FileListCmd);
SET @MaxLogicalNameLength = COALESCE((SELECT MAX(LEN(fl.LogicalName)) FROM #FileList fl), 0);
SELECT @MoveFiles = (SELECT N', MOVE N''' + fl.LogicalName + N''' ' 
    + REPLICATE(N' ', @MaxLogicalNameLength - LEN(fl.LogicalName)) 
    + N'TO N''' + CASE WHEN fl.Type = 'L' THEN @LogPath ELSE @DataPath END 
    + @DBName + N'\' + CASE WHEN fl.FileGroupName = N'PRIMARY' THEN N'System' 
                            WHEN fl.FileGroupName IS NULL THEN N'Log' 
                            ELSE fl.FileGroupName END 
    + N'\' + fl.LogicalName + CASE WHEN fl.Type = 'L' THEN N'.log' 
                                ELSE 
                                    CASE WHEN fl.FileGroupName = N'PRIMARY' THEN N'.mdf'
                                     ELSE N'.ndf' 
                                     END 
                                END + N'''
    '
FROM #FileList fl
FOR XML PATH(''));

SET @MoveFiles = REPLACE(@MoveFiles, N'&#x0D;', N'');
SET @MoveFiles = REPLACE(@MoveFiles, char(10), char(13) + char(10));
SET @MoveFiles = LEFT(@MoveFiles, LEN(@MoveFiles) - 2);

SET @RestoreCmd = N'RESTORE DATABASE ' + @DBName + N'
FROM DISK = N''' + @BackupFile + N''' 
WITH REPLACE 
    , RECOVERY
    , STATS = 5
    ' + @MoveFiles + N';
GO';

IF LEN(@RestoreCmd) > 4000 
BEGIN
    DECLARE @CurrentLen int;
    SET @CurrentLen = 1;
    WHILE @CurrentLen <= LEN(@RestoreCmd)
    BEGIN
        PRINT SUBSTRING(@RestoreCmd, @CurrentLen, 4000);
        SET @CurrentLen = @CurrentLen + 4000;
    END
    RAISERROR (N'Output is chunked into 4,000 char pieces - look for errant line endings!', 14, 1);
END
ELSE
BEGIN
    PRINT @RestoreCmd;
END

The generated RESTORE DATABASE command looks like:

RESTORE DATABASE MyDB
FROM DISK = N'D:\SQLServer\backups\MyDB.bak' 
WITH REPLACE 
    , RECOVERY
    , STATS = 5
    , MOVE N'PRIMARY' TO N'C:\Database\Data\MyDB\system\PRIMARY'
    , MOVE N'LOG'     TO N'C:\Database\Log\MyDB\Log\LOG';
GO

This code has also been tested on the Linux version of SQL Server 2017.

You asked:

Isn't there a simpler way to store the results of a query into a variable and use them? This is a cakewalk in any programming language.

The requirement here is not adding a value to a variable. We need to extract the contents of a set of disparate data into a table. It might be conceptually similar to loading an array from an object. However, in SQL Server the only way you can store the results of command output like the RESTORE HEADERONLY command, is to first insert it into a table, then grab the specific values from the desired table.