sql-server-2008 - SQL Server：检查列的数据类型

Question

如何检查表中的列是否具有特定的数据类型？

例如，如何检查SQL Server表中的列是否属于数据类型char(11)？

Answer 1

select COLUMN_NAME 
from INFORMATION_SCHEMA.COLUMNS
where DATA_TYPE = 'char'
and CHARACTER_MAXIMUM_LENGTH = 11
and TABLE_NAME = 'your_table'

使用syscolumns：

SELECT name FROM SYSCOLUMNS
where length = 11
and xtype = 175 --char type

Answer 2

select case when DATA_TYPE= 'char' then 'T' else 'F' end,    
case when CHARACTER_MAXIMUM_LENGTH = 11 then 'T' else 'F' end    
from INFORMATION_SCHEMA.COLUMNS     
where COLUMN_NAME = 'MY_COLUMN_NAME'     
and TABLE_NAME = 'MY_TABLE_NAME'

Answer 3

查询列数据类型的sql查询

ALTER TABLE table_name MODIFY COLUMN column_name data_type;