如果不存在,我需要添加一个特定的列。我有类似以下的内容,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?


当前回答

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;

如果列确实存在,请执行以下操作:

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

其他回答

下面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是要添加的ColumnName,Object_Id是TableName

调整以下内容以满足您的具体要求:

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

这应该会奏效——仔细检查代码,找出愚蠢的错误;例如,您是否在应用插入的同一数据库上查询INFORMATION_SCHEMA?在这两个语句中,您的表/列名是否有拼写错误?

SQL Server 2005及以后版本:

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·史密斯的版本更短:

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

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')