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?
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
Wheat的答案很好,但它假设您在任何模式或数据库中都没有任何相同的表名/列名对。为了确保安全,使用这个。。。
select *
from Information_Schema.Columns
where Table_Catalog = 'DatabaseName'
and Table_Schema = 'SchemaName'
and Table_Name = 'TableName'
and Column_Name = 'ColumnName'
其他回答
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
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;
IF EXISTS (
SELECT *
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_CATALOG = 'Database Name'
and TABLE_SCHEMA = 'Schema Name'
and TABLE_NAME = 'Table Name'
and COLUMN_NAME = 'Column Name'
and DATA_TYPE = 'Column Type') -- Where statement lines can be deleted.
BEGIN
-- Column exists in table
END
ELSE BEGIN
-- Column does not exist in table
END
还有一种变化。。。
SELECT
Count(*) AS existFlag
FROM
sys.columns
WHERE
[name] = N 'ColumnName'
AND [object_id] = OBJECT_ID(N 'TableName')
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