Removing a Column from a SQL Server Table (Native Client OLE DB provider)
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Azure Synapse Analytics
Analytics Platform System (PDW)
The SQL Server Native Client OLE DB provider exposes the ITableDefinition::DropColumn function. This allows consumers to remove a column from a SQL Server table.
Consumers specify the table name as a Unicode character string in the pwszNamemember of the uName union in the pTableID parameter. The eKindmember of pTableID must be DBKIND_NAME.
The consumer indicates a column name in the pwszNamemember of the uName union in the pColumnID parameter. The column name is a Unicode character string. The eKind member of pColumnID must be DBKIND_NAME.
Example
Code
DBID TableID;
DBID ColumnID;
HRESULT hr;
TableID.eKind = DBKIND_NAME;
TableID.uName.pwszName = L"MyTableName";
ColumnID.eKind = DBKIND_NAME;
ColumnID.uName.pwszName = L"MyColumnName";
hr = m_pITableDefinition->DropColumn(&TableID, &ColumnID);