我有一个SQL Server数据库,我想知道它有什么列和类型。我更喜欢通过查询而不是使用像Enterprise Manager这样的GUI来实现这一点。有办法做到这一点吗?
有几个方法可以获取一个表的元数据:
EXEC sp_help tablename
将返回几个结果集,描述表、它的列和约束。
INFORMATION_SCHEMA视图将为您提供所需的信息,但不幸的是,您必须手动查询这些视图并连接它们。
以防您不想使用stored proc,这里有一个简单的查询版本
select *
from information_schema.columns
where table_name = 'aspnet_Membership'
order by ordinal_position
这些答案的问题在于,你忽略了关键信息。 虽然这是有点混乱,这是一个快速的版本,我提出,以确保它包含相同的信息MySQL描述显示。
Select SC.name AS 'Field', ISC.DATA_TYPE AS 'Type', ISC.CHARACTER_MAXIMUM_LENGTH AS 'Length', SC.IS_NULLABLE AS 'Null', I.is_primary_key AS 'Key', SC.is_identity AS 'Identity'
From sys.columns AS SC
LEFT JOIN sys.index_columns AS IC
ON IC.object_id = OBJECT_ID('dbo.Expenses') AND
IC.column_id = SC.column_id
LEFT JOIN sys.indexes AS I
ON I.object_id = OBJECT_ID('dbo.Expenses') AND
IC.index_id = I.index_id
LEFT JOIN information_schema.columns ISC
ON ISC.TABLE_NAME = 'Expenses'
AND ISC.COLUMN_NAME = SC.name
WHERE SC.object_id = OBJECT_ID('dbo.Expenses')
我在t-sql中写了一个sql* + DESC(RIBE),比如select(显示列注释):
USE YourDB
GO
DECLARE @objectName NVARCHAR(128) = 'YourTable';
SELECT
a.[NAME]
,a.[TYPE]
,a.[CHARSET]
,a.[COLLATION]
,a.[NULLABLE]
,a.[DEFAULT]
,b.[COMMENTS]
-- ,a.[ORDINAL_POSITION]
FROM
(
SELECT
COLUMN_NAME AS [NAME]
,CASE DATA_TYPE
WHEN 'char' THEN DATA_TYPE + '(' + CAST(CHARACTER_MAXIMUM_LENGTH AS VARCHAR) + ')'
WHEN 'numeric' THEN DATA_TYPE + '(' + CAST(NUMERIC_PRECISION AS VARCHAR) + ', ' + CAST(NUMERIC_SCALE AS VARCHAR) + ')'
WHEN 'nvarchar' THEN DATA_TYPE + '(' + CAST(CHARACTER_MAXIMUM_LENGTH AS VARCHAR) + ')'
WHEN 'varbinary' THEN DATA_TYPE + '(' + CAST(CHARACTER_MAXIMUM_LENGTH AS VARCHAR) + ')'
WHEN 'varchar' THEN DATA_TYPE + '(' + CAST(CHARACTER_MAXIMUM_LENGTH AS VARCHAR) + ')'
ELSE DATA_TYPE
END AS [TYPE]
,CHARACTER_SET_NAME AS [CHARSET]
,COLLATION_NAME AS [COLLATION]
,IS_NULLABLE AS [NULLABLE]
,COLUMN_DEFAULT AS [DEFAULT]
,ORDINAL_POSITION
FROM
INFORMATION_SCHEMA.COLUMNS
WHERE
TABLE_NAME = @objectName
) a
FULL JOIN
(
SELECT
CAST(value AS NVARCHAR) AS [COMMENTS]
,CAST(objname AS NVARCHAR) AS [NAME]
FROM
::fn_listextendedproperty ('MS_Description', 'user', 'dbo', 'table', @objectName, 'column', default)
) b
ON a.NAME COLLATE YourCollation = b.NAME COLLATE YourCollation
ORDER BY
a.[ORDINAL_POSITION];
上面提到的select可以在一个系统标记的存储过程中使用,并且可以从你实例的任何数据库中以简单的方式调用它:
USE master;
GO
IF OBJECT_ID('sp_desc', 'P') IS NOT NULL
DROP PROCEDURE sp_desc
GO
CREATE PROCEDURE sp_desc (
@tableName nvarchar(128)
) AS
BEGIN
DECLARE @dbName sysname;
DECLARE @schemaName sysname;
DECLARE @objectName sysname;
DECLARE @objectID int;
DECLARE @tmpTableName varchar(100);
DECLARE @sqlCmd nvarchar(4000);
SELECT @dbName = PARSENAME(@tableName, 3);
IF @dbName IS NULL SELECT @dbName = DB_NAME();
SELECT @schemaName = PARSENAME(@tableName, 2);
IF @schemaName IS NULL SELECT @schemaName = SCHEMA_NAME();
SELECT @objectName = PARSENAME(@tableName, 1);
IF @objectName IS NULL
BEGIN
PRINT 'Object is missing from your function call!';
RETURN;
END;
SELECT @objectID = OBJECT_ID(@dbName + '.' + @schemaName + '.' + @objectName);
IF @objectID IS NULL
BEGIN
PRINT 'Object [' + @dbName + '].[' + @schemaName + '].[' + @objectName + '] does not exist!';
RETURN;
END;
SELECT @tmpTableName = '#tmp_DESC_' + CAST(@@SPID AS VARCHAR) + REPLACE(REPLACE(REPLACE(REPLACE(CAST(CONVERT(CHAR, GETDATE(), 121) AS VARCHAR), '-', ''), ' ', ''), ':', ''), '.', '');
--PRINT @tmpTableName;
SET @sqlCmd = '
USE ' + @dbName + '
CREATE TABLE ' + @tmpTableName + ' (
[NAME] nvarchar(128) NOT NULL
,[TYPE] varchar(50)
,[CHARSET] varchar(50)
,[COLLATION] varchar(50)
,[NULLABLE] varchar(3)
,[DEFAULT] nvarchar(4000)
,[COMMENTS] nvarchar(3750));
INSERT INTO ' + @tmpTableName + '
SELECT
a.[NAME]
,a.[TYPE]
,a.[CHARSET]
,a.[COLLATION]
,a.[NULLABLE]
,a.[DEFAULT]
,b.[COMMENTS]
FROM
(
SELECT
COLUMN_NAME AS [NAME]
,CASE DATA_TYPE
WHEN ''char'' THEN DATA_TYPE + ''('' + CAST(CHARACTER_MAXIMUM_LENGTH AS VARCHAR) + '')''
WHEN ''numeric'' THEN DATA_TYPE + ''('' + CAST(NUMERIC_PRECISION AS VARCHAR) + '', '' + CAST(NUMERIC_SCALE AS VARCHAR) + '')''
WHEN ''nvarchar'' THEN DATA_TYPE + ''('' + CAST(CHARACTER_MAXIMUM_LENGTH AS VARCHAR) + '')''
WHEN ''varbinary'' THEN DATA_TYPE + ''('' + CAST(CHARACTER_MAXIMUM_LENGTH AS VARCHAR) + '')''
WHEN ''varchar'' THEN DATA_TYPE + ''('' + CAST(CHARACTER_MAXIMUM_LENGTH AS VARCHAR) + '')''
ELSE DATA_TYPE
END AS [TYPE]
,CHARACTER_SET_NAME AS [CHARSET]
,COLLATION_NAME AS [COLLATION]
,IS_NULLABLE AS [NULLABLE]
,COLUMN_DEFAULT AS [DEFAULT]
,ORDINAL_POSITION
FROM
INFORMATION_SCHEMA.COLUMNS
WHERE
TABLE_NAME = ''' + @objectName + '''
) a
FULL JOIN
(
SELECT
CAST(value AS NVARCHAR) AS [COMMENTS]
,CAST(objname AS NVARCHAR) AS [NAME]
FROM
::fn_listextendedproperty (''MS_Description'', ''user'', ''' + @schemaName + ''', ''table'', ''' + @objectName + ''', ''column'', default)
) b
ON a.NAME COLLATE Hungarian_CI_AS = b.NAME COLLATE Hungarian_CI_AS
ORDER BY
a.[ORDINAL_POSITION];
SELECT * FROM ' + @tmpTableName + ';'
--PRINT @sqlCmd;
EXEC sp_executesql @sqlCmd;
RETURN;
END;
GO
EXEC sys.sp_MS_marksystemobject sp_desc
GO
执行过程类型:
EXEC sp_desc 'YourDB.YourSchema.YourTable';
如果你想获取当前数据库(和模式)简单类型对象的描述:
EXEC sp_desc 'YourTable';
因为sp_desc是一个系统标记的过程,你甚至可以留下exec命令(无论如何不推荐):
sp_desc 'YourTable';
这是我在EntityFramework反向POCO生成器中使用的代码(可在这里获得)
表的SQL:
SELECT c.TABLE_SCHEMA AS SchemaName,
c.TABLE_NAME AS TableName,
t.TABLE_TYPE AS TableType,
c.ORDINAL_POSITION AS Ordinal,
c.COLUMN_NAME AS ColumnName,
CAST(CASE WHEN IS_NULLABLE = 'YES' THEN 1
ELSE 0
END AS BIT) AS IsNullable,
DATA_TYPE AS TypeName,
ISNULL(CHARACTER_MAXIMUM_LENGTH, 0) AS [MaxLength],
CAST(ISNULL(NUMERIC_PRECISION, 0) AS INT) AS [Precision],
ISNULL(COLUMN_DEFAULT, '') AS [Default],
CAST(ISNULL(DATETIME_PRECISION, 0) AS INT) AS DateTimePrecision,
ISNULL(NUMERIC_SCALE, 0) AS Scale,
CAST(COLUMNPROPERTY(OBJECT_ID(QUOTENAME(c.TABLE_SCHEMA) + '.' + QUOTENAME(c.TABLE_NAME)), c.COLUMN_NAME, 'IsIdentity') AS BIT) AS IsIdentity,
CAST(CASE WHEN COLUMNPROPERTY(OBJECT_ID(QUOTENAME(c.TABLE_SCHEMA) + '.' + QUOTENAME(c.TABLE_NAME)), c.COLUMN_NAME, 'IsIdentity') = 1 THEN 1
WHEN COLUMNPROPERTY(OBJECT_ID(QUOTENAME(c.TABLE_SCHEMA) + '.' + QUOTENAME(c.TABLE_NAME)), c.COLUMN_NAME, 'IsComputed') = 1 THEN 1
WHEN DATA_TYPE = 'TIMESTAMP' THEN 1
ELSE 0
END AS BIT) AS IsStoreGenerated,
CAST(CASE WHEN pk.ORDINAL_POSITION IS NULL THEN 0
ELSE 1
END AS BIT) AS PrimaryKey,
ISNULL(pk.ORDINAL_POSITION, 0) PrimaryKeyOrdinal,
CAST(CASE WHEN fk.COLUMN_NAME IS NULL THEN 0
ELSE 1
END AS BIT) AS IsForeignKey
FROM INFORMATION_SCHEMA.COLUMNS c
LEFT OUTER JOIN (SELECT u.TABLE_SCHEMA,
u.TABLE_NAME,
u.COLUMN_NAME,
u.ORDINAL_POSITION
FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE u
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc
ON u.TABLE_SCHEMA = tc.CONSTRAINT_SCHEMA
AND u.TABLE_NAME = tc.TABLE_NAME
AND u.CONSTRAINT_NAME = tc.CONSTRAINT_NAME
WHERE CONSTRAINT_TYPE = 'PRIMARY KEY') pk
ON c.TABLE_SCHEMA = pk.TABLE_SCHEMA
AND c.TABLE_NAME = pk.TABLE_NAME
AND c.COLUMN_NAME = pk.COLUMN_NAME
LEFT OUTER JOIN (SELECT DISTINCT
u.TABLE_SCHEMA,
u.TABLE_NAME,
u.COLUMN_NAME
FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE u
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc
ON u.TABLE_SCHEMA = tc.CONSTRAINT_SCHEMA
AND u.TABLE_NAME = tc.TABLE_NAME
AND u.CONSTRAINT_NAME = tc.CONSTRAINT_NAME
WHERE CONSTRAINT_TYPE = 'FOREIGN KEY') fk
ON c.TABLE_SCHEMA = fk.TABLE_SCHEMA
AND c.TABLE_NAME = fk.TABLE_NAME
AND c.COLUMN_NAME = fk.COLUMN_NAME
INNER JOIN INFORMATION_SCHEMA.TABLES t
ON c.TABLE_SCHEMA = t.TABLE_SCHEMA
AND c.TABLE_NAME = t.TABLE_NAME
WHERE c.TABLE_NAME NOT IN ('EdmMetadata', '__MigrationHistory')
外键SQL:
SELECT FK.name AS FK_Table,
FkCol.name AS FK_Column,
PK.name AS PK_Table,
PkCol.name AS PK_Column,
OBJECT_NAME(f.object_id) AS Constraint_Name,
SCHEMA_NAME(FK.schema_id) AS fkSchema,
SCHEMA_NAME(PK.schema_id) AS pkSchema,
PkCol.name AS primarykey,
k.constraint_column_id AS ORDINAL_POSITION
FROM sys.objects AS PK
INNER JOIN sys.foreign_keys AS f
INNER JOIN sys.foreign_key_columns AS k
ON k.constraint_object_id = f.object_id
INNER JOIN sys.indexes AS i
ON f.referenced_object_id = i.object_id
AND f.key_index_id = i.index_id
ON PK.object_id = f.referenced_object_id
INNER JOIN sys.objects AS FK
ON f.parent_object_id = FK.object_id
INNER JOIN sys.columns AS PkCol
ON f.referenced_object_id = PkCol.object_id
AND k.referenced_column_id = PkCol.column_id
INNER JOIN sys.columns AS FkCol
ON f.parent_object_id = FkCol.object_id
AND k.parent_column_id = FkCol.column_id
ORDER BY FK_Table, FK_Column
扩展属性:
SELECT s.name AS [schema],
t.name AS [table],
c.name AS [column],
value AS [property]
FROM sys.extended_properties AS ep
INNER JOIN sys.tables AS t
ON ep.major_id = t.object_id
INNER JOIN sys.schemas AS s
ON s.schema_id = t.schema_id
INNER JOIN sys.columns AS c
ON ep.major_id = c.object_id
AND ep.minor_id = c.column_id
WHERE class = 1
ORDER BY t.name
CREATE PROCEDURE [dbo].[describe]
(
@SearchStr nvarchar(max)
)
AS
BEGIN
SELECT
CONCAT([COLUMN_NAME],' ',[DATA_TYPE],' ',[CHARACTER_MAXIMUM_LENGTH],' ',
(SELECT CASE [IS_NULLABLE] WHEN 'NO' THEN 'NOT NULL' ELSE 'NULL' END),
(SELECT CASE WHEN [COLUMN_DEFAULT] IS NULL THEN '' ELSE CONCAT(' DEFAULT ',[COLUMN_DEFAULT]) END)
) AS DESCRIPTION
FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME LIKE @SearchStr
END
请使用以下sql查询;这对我的案子很管用。
select * FROM INFORMATION_SCHEMA.Columns where table_name = 'tablename';
除了在其他答案中显示的方法,你还可以使用
SELECT TOP 0 * FROM table_name
这将为您提供每个列的名称,其中没有结果,并且几乎立即以最小的开销完成。
SQL Server中与Oracle的describe命令等价的是存储的proc sp_help
describe命令提供了列名、类型、长度等信息。
在SQL Server中,假设你想在数据库'mydb'中的模式'myschema'中描述一个表'mytable',你可以这样做:
USE mydb;
exec sp_help 'myschema.mytable';
我喜欢这种格式:
name DataType Collation Constraints PK FK Comment
id int NOT NULL IDENTITY PK Order Line Id
pid int NOT NULL tbl_orders Order Id
itemCode varchar(10) Latin1_General_CI_AS NOT NULL Product Code
所以我用了这个:
DECLARE @tname varchar(100) = 'yourTableName';
SELECT col.name,
CASE typ.name
WHEN 'nvarchar' THEN 'nvarchar('+CAST((col.max_length / 2) as varchar)+')'
WHEN 'varchar' THEN 'varchar('+CAST(col.max_length as varchar)+')'
WHEN 'char' THEN 'char('+CAST(col.max_length as varchar)+')'
WHEN 'nchar' THEN 'nchar('+CAST((col.max_length / 2) as varchar)+')'
WHEN 'binary' THEN 'binary('+CAST(col.max_length as varchar)+')'
WHEN 'varbinary' THEN 'varbinary('+CAST(col.max_length as varchar)+')'
WHEN 'numeric' THEN 'numeric('+CAST(col.precision as varchar)+(CASE WHEN col.scale = 0 THEN '' ELSE ','+CAST(col.scale as varchar) END) +')'
WHEN 'decimal' THEN 'decimal('+CAST(col.precision as varchar)+(CASE WHEN col.scale = 0 THEN '' ELSE ','+CAST(col.scale as varchar) END) +')'
ELSE typ.name
END DataType,
ISNULL(col.collation_name,'') Collation,
CASE WHEN col.is_nullable = 0 THEN 'NOT NULL ' ELSE '' END + CASE WHEN col.is_identity = 1 THEN 'IDENTITY' ELSE '' END Constraints,
ISNULL((SELECT 'PK'
FROM sys.key_constraints kc INNER JOIN
sys.tables tb ON tb.object_id = kc.parent_object_id INNER JOIN
sys.indexes si ON si.name = kc.name INNER JOIN
sys.index_columns sic ON sic.index_id = si.index_id AND sic.object_id = si.object_id
WHERE kc.type = 'PK'
AND tb.name = @tname
AND sic.column_id = col.column_id),'') PK,
ISNULL((SELECT (SELECT name FROM sys.tables st WHERE st.object_id = fkc.referenced_object_id)
FROM sys.foreign_key_columns fkc INNER JOIN
sys.columns c ON c.column_id = fkc.parent_column_id AND fkc.parent_object_id = c.object_id INNER JOIN
sys.tables t ON t.object_id = c.object_id
WHERE t.name = tab.name
AND c.name = col.name),'') FK,
ISNULL((SELECT value
FROM sys.extended_properties
WHERE major_id = tab.object_id
AND minor_id = col.column_id),'') Comment
FROM sys.columns col INNER JOIN
sys.tables tab ON tab.object_id = col.object_id INNER JOIN
sys.types typ ON typ.system_type_id = col.system_type_id
WHERE tab.name = @tname
AND typ.name != 'sysname'
ORDER BY col.column_id;
SELECT C.COLUMN_NAME, C.IS_NULLABLE, C.DATA_TYPE, TC.CONSTRAINT_TYPE, C.COLUMN_DEFAULT
FROM INFORMATION_SCHEMA.COLUMNS AS C
FULL JOIN INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE AS CC ON C.COLUMN_NAME = CC.COLUMN_NAME
FULL JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS TC ON CC.CONSTRAINT_NAME = TC.CONSTRAINT_NAME
WHERE C.TABLE_NAME = '<Table Name>';
样例输出
如果你正在使用Brent Ozar团队的FirstResponderKit,你也可以运行这个查询:
exec sp_blitzindex @tablename='MyTable'
它将返回关于表的所有信息:
索引及其使用统计信息(读、写、锁等)、空间 二手和其他 缺失索引 列 外键 统计内容
当然,它不是一个系统,也不像sp_help或sp_columns那样通用,但它返回关于表的所有可能信息,我认为值得在您的环境中创建它并在这里提到它。
除了上述问题,如果我们在DB中有像db_name.dbo这样的表。Table_name,我们可以使用以下步骤
连接DB 使用db_name; 使用EXEC sp_help,不要忘记将表名设置为'dbo。表名'如果你有dbo作为schema。 Exec sp_help 'dbo.table_name'
这应该有用!
下面的查询将提供类似于python、Pandas库中的info()函数的输出。
USE [Database_Name]
IF OBJECT_ID('tempdo.dob.#primary_key', 'U') IS NOT NULL DROP TABLE #primary_key
SELECT
CONS_T.TABLE_CATALOG,
CONS_T.TABLE_SCHEMA,
CONS_T.TABLE_NAME,
CONS_C.COLUMN_NAME,
CONS_T.CONSTRAINT_TYPE,
CONS_T.CONSTRAINT_NAME
INTO #primary_key
FROM
INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS CONS_T
JOIN INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE AS CONS_C ON CONS_C.CONSTRAINT_NAME= CONS_T.CONSTRAINT_NAME
SELECT
SMA.name AS [Schema Name],
ST.name AS [Table Name],
SC.column_id AS [Column Order],
SC.name AS [Column Name],
PKT.CONSTRAINT_TYPE,
PKT.CONSTRAINT_NAME,
SC.system_type_id,
STP.name AS [Data Type],
SC.max_length,
SC.precision,
SC.scale,
SC.is_nullable,
SC.is_masked
FROM sys.tables AS ST
JOIN sys.schemas AS SMA ON SMA.schema_id = ST.schema_id
JOIN sys.columns AS SC ON SC.object_id = ST.object_id
JOIN sys.types AS STP ON STP.system_type_id = SC.system_type_id
LEFT JOIN #primary_key AS PKT ON PKT.TABLE_SCHEMA = SMA.name
AND PKT.TABLE_NAME = ST.name
AND PKT.COLUMN_NAME = SC.name
ORDER BY ST.name ASC, SMA.name ASC
试一试:
EXEC [ServerName].[DatabaseName].dbo.sp_columns 'TableName'
你可以得到一些表结构的信息,比如:
Table_qualifier, table_owner, table_name, column_name, data_type, type_name…
首先连接到你的数据库,
使用DB_name
然后
exec sp_help '生产。Et_Issue”
这里的'production'是模式名。如果你没有图式, 您可以简单地写入sp_help table_name
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