我需要在SQL server上编写一个查询,以获得特定表中的列列表,其相关数据类型(长度)以及它们是否不为空。我已经做到了这么多。
但现在我还需要得到,在同一个表中,对一个列- TRUE,如果该列是一个主键。
我该怎么做呢?
我的期望输出是:
Column name | Data type | Length | isnull | Pk
我需要在SQL server上编写一个查询,以获得特定表中的列列表,其相关数据类型(长度)以及它们是否不为空。我已经做到了这么多。
但现在我还需要得到,在同一个表中,对一个列- TRUE,如果该列是一个主键。
我该怎么做呢?
我的期望输出是:
Column name | Data type | Length | isnull | Pk
当前回答
为了确保获得正确的长度,需要将unicode类型视为一种特殊情况。参见下面的代码。
更多信息请参见:https://msdn.microsoft.com/en-us/library/ms176106.aspx
SELECT
c.name 'Column Name',
t.name,
t.name +
CASE WHEN t.name IN ('char', 'varchar','nchar','nvarchar') THEN '('+
CASE WHEN c.max_length=-1 THEN 'MAX'
ELSE CONVERT(VARCHAR(4),
CASE WHEN t.name IN ('nchar','nvarchar')
THEN c.max_length/2 ELSE c.max_length END )
END +')'
WHEN t.name IN ('decimal','numeric')
THEN '('+ CONVERT(VARCHAR(4),c.precision)+','
+ CONVERT(VARCHAR(4),c.Scale)+')'
ELSE '' END
as "DDL name",
c.max_length 'Max Length in Bytes',
c.precision ,
c.scale ,
c.is_nullable,
ISNULL(i.is_primary_key, 0) 'Primary Key'
FROM
sys.columns c
INNER JOIN
sys.types t ON c.user_type_id = t.user_type_id
LEFT OUTER JOIN
sys.index_columns ic ON ic.object_id = c.object_id AND ic.column_id = c.column_id
LEFT OUTER JOIN
sys.indexes i ON ic.object_id = i.object_id AND ic.index_id = i.index_id
WHERE
c.object_id = OBJECT_ID('YourTableName')
其他回答
查找数据类型和长度的组合结果,并以“NULL”和“非空”的形式为空。
SELECT c.name AS 'Column Name',
t.name + '(' + cast(c.max_length as varchar(50)) + ')' As 'DataType',
case
WHEN c.is_nullable = 0 then 'null' else 'not null'
END AS 'Constraint'
FROM sys.columns c
JOIN sys.types t
ON c.user_type_id = t.user_type_id
WHERE c.object_id = Object_id('TableName')
你会发现结果如下所示。
谢谢你!
在查询编辑器中选择表名并按Alt+F1,它将带来表的所有信息。
我有点惊讶居然没人提
sp_help 'mytable'
SELECT COLUMN_NAME, IS_NULLABLE, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH FROM information_schema.columns WHERE table_name = '<name_of_table_or_view>'
在上面的语句中运行SELECT *,以查看information_schema. schema是什么。列的回报。
这个问题之前已经回答过了- https://stackoverflow.com/a/11268456/6169225
Marc_s的答案很好,但如果主键列出现在其他索引中,这些列会出现不止一次,那么它就有一个缺陷。如。
演示:
create table dbo.DummyTable
(
id int not null identity(0,1) primary key,
Msg varchar(80) null
);
create index NC_DummyTable_id ON DummyTable(id);
下面是我用来解决这个问题的存储过程:
create or alter procedure dbo.GetTableColumns
(
@schemaname nvarchar(128),
@tablename nvarchar(128)
)
AS
BEGIN
SET NOCOUNT ON;
with ctePKCols as
(
select
i.object_id,
ic.column_id
from
sys.indexes i
join sys.index_columns ic ON i.object_id = ic.object_id AND i.index_id = ic.index_id
where
i.is_primary_key = 1
)
SELECT
c.name AS column_name,
t.name AS typename,
c.max_length AS MaxLength,
c.precision,
c.scale,
c.is_nullable,
is_primary_key = CASE WHEN ct.column_id IS NOT NULL THEN 1 ELSE 0 END
FROM
sys.columns c
JOIN sys.types t ON t.user_type_id = c.user_type_id
LEFT JOIN ctePKCols ct ON ct.column_id = c.column_id AND ct.object_id = c.object_id
WHERE
c.object_ID = OBJECT_ID(quotename(@schemaname) + '.' + quotename(@tablename))
END
GO
exec dbo.GetTableColumns 'dbo', 'DummyTable'