如何检查SQL Server表中是否存在列？

Question

如果不存在,我需要添加一个特定的列.我有类似以下内容,但它总是返回false:

IF EXISTS(SELECT *
          FROM   INFORMATION_SCHEMA.COLUMNS
          WHERE  TABLE_NAME = 'myTableName'
                 AND COLUMN_NAME = 'myColumnName') 

如何检查SQL Server数据库的表中是否存在列？

Answer 1

SQL Server 2005以后:

IF EXISTS(SELECT 1 FROM sys.columns 
          WHERE Name = N'columnName'
          AND Object_ID = Object_ID(N'schemaName.tableName'))
BEGIN
    -- Column Exists
END

马丁史密斯的版本较短:

IF COL_LENGTH('schemaName.tableName', 'columnName') IS NOT NULL
BEGIN
    -- Column Exists
END

Answer 2

更简洁的版本

IF COL_LENGTH('table_name','column_name') IS NULL
BEGIN
/* Column does not exist or caller does not have permission to view the object */
END

关于查看元数据的权限的观点适用于所有答案,而不仅仅是这一点.

请注意,第一个参数表名称COL_LENGTH可以根据需要采用一个,两个或三个部分名称格式.

引用不同数据库中的表的示例是

COL_LENGTH('AdventureWorks2012.HumanResources.Department','ModifiedDate')

与使用元数据视图相比,这个答案的一个不同之处在于元数据函数,例如COL_LENGTH始终只返回有关已提交更改的数据,而不管有效的隔离级别如何.

Answer 3

调整以下内容以满足您的特定要求:

if not exists (select
                     column_name
               from
                     INFORMATION_SCHEMA.columns
               where
                     table_name = 'MyTable'
                     and column_name = 'MyColumn')
    alter table MyTable add MyColumn int

编辑以处理编辑问题:这应该工作 - 仔细查看代码中的愚蠢错误; 您是否在应用插入的同一数据库中查询INFORMATION_SCHEMA？在任何一个语句中,您的表/列名称中是否有拼写错误？

Answer 4

试试这个...

IF NOT EXISTS(
  SELECT TOP 1 1
  FROM INFORMATION_SCHEMA.COLUMNS
  WHERE 
    [TABLE_NAME] = 'Employees'
    AND [COLUMN_NAME] = 'EmployeeID')
BEGIN
  ALTER TABLE [Employees]
    ADD [EmployeeID] INT NULL
END

Answer 5

我更喜欢INFORMATION_SCHEMA.COLUMNS系统表,因为Microsoft不保证在版本之间保留系统表.例如,dbo.syscolumns仍然可以在SQL 2008中使用,但它已被弃用,并且可以在将来的任何时候删除.

Answer 6

您可以使用信息架构系统视图来查找您感兴趣的表的几乎所有内容:

SELECT *
  FROM INFORMATION_SCHEMA.COLUMNS
 WHERE TABLE_NAME = 'yourTableName'
 ORDER BY ORDINAL_POSITION

您还可以使用Information_schema视图查询视图,存储过程以及有关数据库的任何内容.

Answer 7

对于正在检查列存在的人来说.

在SQL Server 2016中,您可以使用新的DIE语句而不是大IF包装器

ALTER TABLE Table_name DROP COLUMN IF EXISTS Column_name

Answer 8

首先检查table/ column(id/ name)组合是否存在于dbo.syscolumns(包含字段定义的内部SQL Server表)中,如果没有,则发出相应的ALTER TABLE查询以添加它.例如:

IF NOT EXISTS ( SELECT  *
            FROM    syscolumns
            WHERE   id = OBJECT_ID('Client')
                    AND name = 'Name' ) 
ALTER TABLE Client
ADD Name VARCHAR(64) NULL

Answer 9

尝试类似的东西:

CREATE FUNCTION ColumnExists(@TableName varchar(100), @ColumnName varchar(100))
RETURNS varchar(1) AS
BEGIN
DECLARE @Result varchar(1);
IF EXISTS (SELECT * FROM INFORMATION_SCHEMA.Columns WHERE TABLE_NAME = @TableName AND COLUMN_NAME = @ColumnName)
BEGIN
    SET @Result = 'T'
END
ELSE
BEGIN
    SET @Result = 'F'
END
RETURN @Result;
END
GO

GRANT EXECUTE ON  [ColumnExists] TO [whoever]
GO

然后像这样使用它:

IF ColumnExists('xxx', 'yyyy') = 'F'
BEGIN
  ALTER TABLE xxx
  ADD yyyyy varChar(10) NOT NULL
END
GO

它应该适用于SQL Server 2000和SQL Server 2005.不确定SQL Server 2008,但不明白为什么不.

Answer 10

我的一位好朋友和同事向我展示了如何使用IFSQL函数块OBJECT_ID和COLUMNPROPERTYSQL SERVER 2005+来检查列.您可以使用类似于以下内容的内容:

你可以在这里看到自己

IF (OBJECT_ID(N'[dbo].[myTable]') IS NOT NULL AND
    COLUMNPROPERTY( OBJECT_ID(N'[dbo].[myTable]'), 'ThisColumnDoesNotExist', 'ColumnId') IS NULL)
BEGIN
    SELECT 'Column does not exist -- You can add TSQL to add the column here'
END

Answer 11

declare @myColumn   as nvarchar(128)
set @myColumn = 'myColumn'
if not exists (
    select  1
    from    information_schema.columns columns 
    where   columns.table_catalog   = 'myDatabase'
        and columns.table_schema    = 'mySchema' 
        and columns.table_name      = 'myTable' 
        and columns.column_name     = @myColumn
    )
begin
    exec('alter table myDatabase.mySchema.myTable add'
    +'    ['+@myColumn+'] bigint       null')
end

Answer 12

这在SQL 2000中对我有用:

IF EXISTS 
(
    SELECT * 
    FROM INFORMATION_SCHEMA.COLUMNS 
    WHERE table_name = 'table_name' 
    AND column_name = 'column_name'
)
BEGIN
...
END

Answer 13

试试这个

SELECT COLUMNS.*
FROM   INFORMATION_SCHEMA.COLUMNS COLUMNS,
       INFORMATION_SCHEMA.TABLES TABLES
WHERE  COLUMNS.TABLE_NAME = TABLES.TABLE_NAME
       AND Upper(COLUMNS.COLUMN_NAME) = Upper('column_name') 

Answer 14

我需要类似于SQL SERVER 2000,正如@Mitch指出的那样,这只适用于2005+.

它应该对其他人有帮助吗,这最终对我有用:

if exists (
    select * 
    from 
        sysobjects, syscolumns 
    where 
        sysobjects.id = syscolumns.id 
        and sysobjects.name = 'table' 
        and syscolumns.name = 'column')

Answer 15

if exists (
  select * 
  from INFORMATION_SCHEMA.COLUMNS 
  where TABLE_NAME = '<table_name>' 
  and COLUMN_NAME = '<column_name>'
) begin
  print 'Column you have specified exists'
end else begin
  print 'Column does not exist'
end

Answer 16

IF NOT EXISTS( SELECT NULL
            FROM INFORMATION_SCHEMA.COLUMNS
           WHERE table_name = 'TableName'
             AND table_schema = 'SchemaName'
             AND column_name = 'ColumnName')  BEGIN

  ALTER TABLE [SchemaName].[TableName] ADD [ColumnName] int(1) NOT NULL default '0';

END;

Answer 17

select distinct object_name(sc.id)
from syscolumns sc,sysobjects so  
where sc.name like '%col_name%' and so.type='U'

Answer 18

接受答案的临时表版本:

if (exists(select 1 
             from tempdb.sys.columns  
            where Name = 'columnName'
              and Object_ID = object_id('tempdb..#tableName')))
begin
...
end

Answer 19

Wheat的答案很好,但假设您在任何架构或数据库中没有任何相同的表名/列名对.为了使其安全,请使用此...

select *
from Information_Schema.Columns
where Table_Catalog = 'DatabaseName'
  and Table_Schema = 'SchemaName'
  and Table_Name = 'TableName'
  and Column_Name = 'ColumnName'

Answer 20

有几种方法可以检查列的存在.我强烈建议使用INFORMATION_SCHEMA.COLUMNS它,因为它是为了与用户沟通而创建的.考虑以下表格:

 sys.objects
 sys.columns

甚至可以检查一些其他访问方法 system catalog.

此外,无需使用SELECT *,只需通过测试NULL value

IF EXISTS(
           SELECT NULL 
           FROM INFORMATION_SCHEMA.COLUMNS
           WHERE
             TABLE_NAME = 'myTableName'
             AND COLUMN_NAME = 'myColumnName'
         ) 

Answer 21

另一个贡献是以下示例，如果该列不存在，则添加该列。

    USE [Northwind]
    GO

    IF NOT EXISTS(SELECT * FROM INFORMATION_SCHEMA.COLUMNS
                    WHERE TABLE_NAME = 'Categories'
                        AND COLUMN_NAME = 'Note')
    BEGIN

    ALTER TABLE Categories ADD Note NVARCHAR(800) NULL

    END
    GO

Answer 22

这是我用来管理数据库中列添加的简单脚本：

IF NOT EXISTS (
        SELECT *
        FROM sys.Columns
        WHERE Name = N'QbId'
            AND Object_Id = Object_Id(N'Driver')
        )
BEGIN
    ALTER TABLE Driver ADD QbId NVARCHAR(20) NULL
END
ELSE
BEGIN
    PRINT 'QbId is already added on Driver'
END

在此示例中，Name是ColumnName要添加的和Object_Id是TableName

Answer 23

最简单易懂的解决方案之一是：

IF COL_LENGTH('Table_Name','Column_Name') IS NULL
 BEGIN
    -- Column Not Exists, implement your logic
 END 
ELSE
 BEGIN
    -- Column Exists, implement your logic
 END

Answer 24

如果列不存在，请执行以下操作：

BEGIN
    IF (COL_LENGTH('[dbo].[Table]', 'Column ') IS NULL)
    BEGIN
        //Do something
    END
END;

如果列存在，请执行某些操作：

BEGIN
    IF (COL_LENGTH('[dbo].[Table]', 'Column ') IS NOT NULL)
    BEGIN
        //Do something
    END
END;