[英]why does this Dynamic Sql Statement fail?
這沒有任何問題:
select COLUMN_NAME,DATA_TYPE,CHARACTER_MAXIMUM_LENGTH,IS_NULLABLE
from [AdventureWorks2012].INFORMATION_SCHEMA.COLUMNS WHERE table_name='employee';
但是,當它轉移到動態語句時,它總是失敗:
begin
DECLARE @sqlstatement VARCHAR(MAX);
DECLARE @TableName varchar(max)='employee';
set @sqlstatement='select COLUMN_NAME,DATA_TYPE,CHARACTER_MAXIMUM_LENGTH,IS_NULLABLE
from [AdventureWorks2012].INFORMATION_SCHEMA.COLUMNS WHERE table_name='+@TableName;
print (@sqlstatement);
EXECUTE(@sqlstatement);
end
錯誤說:無效的列名稱'employee'
你應該用單引號包裝它,因為列table_name
是字符串,
set @sqlstatement='select COLUMN_NAME,DATA_TYPE,CHARACTER_MAXIMUM_LENGTH,IS_NULLABLE
from [AdventureWorks2012].INFORMATION_SCHEMA.COLUMNS WHERE table_name='''+@TableName+'''';
使用sys.sp_executesql
更希望執行動態SQL,所以試試這個 -
DECLARE @SQL NVARCHAR(MAX);
DECLARE @TableName SYSNAME = 'Employee';
SELECT @SQL = '
USE [AdventureWorks2012];
SELECT
COLUMN_NAME = c.name
, DATA_TYPE = TYPE_NAME(c.user_type_id)
, CHARACTER_MAXIMUM_LENGTH = c.max_length
, IS_NULLABLE = c.is_nullable
FROM sys.columns c
JOIN sys.objects o ON c.[object_id] = o.[object_id]
WHERE o.name = ''' + @TableName + '''';
PRINT @SQL;
EXEC sys.sp_executesql @SQL;
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.