如何嵌套SQL语句实现按Description映射ChargeType并返回单一数据集

需嵌套条件语句，返回一个根据description字段确定ChargeType的单一数据集。这是一个ETL脚本，用于从源端提取数据，并将各类description映射到目标系统所需的选项集。

if (invoice_detail.description like 'Net Rental' or invoice_detail.description like 'Balance of Minimum Guarantee') 

    Select
        id.code_invoice,
        'License Fee' as ChargeType,
        id.amount,
        id.vat_amount,
        id.original_amount,
        id.original_amount - id.original_vat_amount as netTotal
        
        from invoice_detail id order by code_invoice desc;
         
        
if  (invoice_detail.description like 'FBM Download')

    Select
        id.code_invoice,
        'DLM' as ChargeType,
        id.amount,
        id.vat_amount,
        id.original_amount,
        id.original_amount - id.original_vat_amount as netTotal
        
        from invoice_detail id order by code_invoice desc;

内容的提问来源于stack exchange，提问作者user2903459