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

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!

其他回答

select
      c.name as [column name], 
      t.name as [type name],
      tbl.name as [table name]
from sys.columns c
         inner join sys.types t 
      on c.system_type_id = t.system_type_id 
         inner join sys.tables tbl
      on c.object_id = tbl.object_id
where
      c.object_id = OBJECT_ID('YourTableName1') 
          and 
      t.name like '%YourSearchDataType%'
union
(select
      c.name as [column name], 
      t.name as [type name],
      tbl.name as [table name]
from sys.columns c
         inner join sys.types t 
      on c.system_type_id = t.system_type_id 
         inner join sys.tables tbl
      on c.object_id = tbl.object_id
where
      c.object_id = OBJECT_ID('YourTableName2') 
          and 
      t.name like '%YourSearchDataType%')
union
(select
      c.name as [column name], 
      t.name as [type name],
      tbl.name as [table name]
from sys.columns c
         inner join sys.types t 
      on c.system_type_id = t.system_type_id 
         inner join sys.tables tbl
      on c.object_id = tbl.object_id
where
      c.object_id = OBJECT_ID('YourTableName3') 
          and 
      t.name like '%YourSearchDataType%')
order by tbl.name

根据一个数据库中三个不同表的搜索数据类型,搜索哪个列在哪个表中。这个查询可以扩展到'n'个表。

扩展Alex的答案,您可以这样做以获得PK约束

Select C.COLUMN_NAME, C.DATA_TYPE, C.CHARACTER_MAXIMUM_LENGTH, C.NUMERIC_PRECISION, C.IS_NULLABLE, TC.CONSTRAINT_NAME
From INFORMATION_SCHEMA.COLUMNS As C
    Left Join INFORMATION_SCHEMA.TABLE_CONSTRAINTS As TC
      On TC.TABLE_SCHEMA = C.TABLE_SCHEMA
          And TC.TABLE_NAME = C.TABLE_NAME
          And TC.CONSTRAINT_TYPE = 'PRIMARY KEY'
Where C.TABLE_NAME = 'Table'

我一定是错过了您想要一个标记来确定给定的列是否是PK的一部分,而不是PK约束的名称。你可以用:

Select C.COLUMN_NAME, C.DATA_TYPE, C.CHARACTER_MAXIMUM_LENGTH
    , C.NUMERIC_PRECISION, C.NUMERIC_SCALE
    , C.IS_NULLABLE
    , Case When Z.CONSTRAINT_NAME Is Null Then 0 Else 1 End As IsPartOfPrimaryKey
From INFORMATION_SCHEMA.COLUMNS As C
    Outer Apply (
                Select CCU.CONSTRAINT_NAME
                From INFORMATION_SCHEMA.TABLE_CONSTRAINTS As TC
                    Join INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE As CCU
                        On CCU.CONSTRAINT_NAME = TC.CONSTRAINT_NAME
                Where TC.TABLE_SCHEMA = C.TABLE_SCHEMA
                    And TC.TABLE_NAME = C.TABLE_NAME
                    And TC.CONSTRAINT_TYPE = 'PRIMARY KEY'
                    And CCU.COLUMN_NAME = C.COLUMN_NAME
                ) As Z
Where C.TABLE_NAME = 'Table'

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!

IF EXISTS (SELECT 1 FROM INFORMATION_SCHEMA.TABLES 
     WHERE TABLE_TYPE = 'BASE TABLE' AND TABLE_NAME = 'Table')
      BEGIN
        SELECT COLS.COLUMN_NAME, COLS.DATA_TYPE, COLS.CHARACTER_MAXIMUM_LENGTH, 
              (SELECT 'Yes' FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS TC JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE KCU
                              ON COLS.TABLE_NAME = TC.TABLE_NAME 
                             AND TC.CONSTRAINT_TYPE = 'PRIMARY KEY'
                             AND KCU.TABLE_NAME = TC.TABLE_NAME
                             AND KCU.CONSTRAINT_NAME = TC.CONSTRAINT_NAME
                             AND KCU.COLUMN_NAME = COLS.COLUMN_NAME) AS KeyX
        FROM INFORMATION_SCHEMA.COLUMNS COLS WHERE TABLE_NAME = 'Table' ORDER BY KeyX DESC, COLUMN_NAME
      END

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')