How to Select All Database Fields Except One Specific Field?

Retrieve all fields but exclude specific fields

In the process of finding a more efficient way to retrieve specific fields while excluding BLOB/TEXT fields, you question the existence of a "SELECT * EXCEPT" clause. Although this functionality is not standard in most RDBMS, you are looking for an alternative that allows you to retrieve all fields except a specific field.

*Risks of using SELECT **

Many responses expressed concerns about the risks associated with using "SELECT *", including performance issues and the possibility of sensitive data leakage. While these concerns are valid, you emphasize that your intended use case is strictly for debugging purposes, where performance and data security are less important.

Dynamic SQL Solution

The solution proposed in the accepted answer employs dynamic SQL to build a query string that retrieves all columns of a specified table but excludes one specific column. It utilizes the syscolumns and sysobjects tables, iterates over the available columns and builds queries dynamically. Here’s a breakdown of the technology:

<code class="language-sql">-- 初始化变量
declare @sql varchar(8000), @table_id int, @col_id int
-- 获取'MY_Table'的表ID
set @table_id = (select id from sysobjects where name = 'MY_Table')
-- 获取所有列的列ID，但不包括'description'
select @col_id = min(colid) from syscolumns where id = @table_id and name <> 'description'
-- 循环遍历所有剩余列
while (@col_id is not null) begin
    -- 将列名附加到查询字符串
    select @sql = @sql + name from syscolumns where id = @table_id and colid = @col_id
    -- 获取下一列的列ID
    select @col_id = min(colid) from syscolumns where id = @table_id and colid > @col_id and name <> 'description'
    -- 添加逗号以分隔列（如有必要）
    if (@col_id is not null) set @sql = @sql + ','
    -- 打印已构建的查询字符串（用于调试目的）
    print @sql
end
-- 完成查询字符串
set @sql = @sql + ' from MY_table'
-- 执行查询
exec sp_executesql @sql</code>

Note: Dynamic SQL should be used with caution as it can create potential security vulnerabilities. Ensure that the database user executing the query has appropriate permissions and that the query is constructed correctly to avoid unexpected results. It is recommended to use parameterized queries to avoid SQL injection.

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