爲什麼此查詢匹配錯誤的數據庫名稱？

Question

爲什麼'TestDatabase2'也匹配'TestDatabase'？同樣，'D2'也匹配'D'。

exec sp_executesql N'SELECT TOP 1 
        sdb.name AS DbName, 
        bus.backup_start_date AS LastBackUpTime, 
        bus.type AS Type 
       FROM 
        sys.sysdatabases sdb 
       LEFT OUTER JOIN 
        msdb.dbo.backupset bus 
       ON 
        bus.database_name = sdb.NAME 
        AND 
        bus.type = @backupType 
       WHERE 
        sdb.name = @dbname 
       ORDER BY 
        LastBackUpTime DESC',N'@dbName nvarchar(12),@backupType nvarchar(1)',@dbName=N'TestDatabase',@backupType=N'D' 

Answer 1

您的數據庫名稱參數是NVARCHAR(12)。

猜猜TestDatabase多少個字符是;）

SELECT CAST('TestDatabase' as NVARCHAR(12)), CAST('TestDatabase12314' as NVARCHAR(12)) 

你應該讓一個NVARCHAR(128)或SYSNAME，這是msdb.dbo.backupset.database_name和sys.databases.name列的長度。