Php 在mysql中，如何使用子查询或内部查询在单个查询中组合两个查询

如果我把你的要求弄对了，那就行了

select sub.sub_product_image_path, sub.sub_product_id 
    from `portal_products(sub category)` sub , 
         `portal_products(main category)`main 
  where sub.product_id=main.product_id ;

select sub.sub_product_image_path, sub.sub_product_id 
    from `portal_products(sub category)` sub  
  where sub.product_id=35;

或

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使用Union或Union ALL将“门户_产品（子类别）”描述为表名的错误选择将是轻描淡写的

select sub.sub_product_image_path,sub.sub_product_id 
 from `portal_products(sub category)` sub 
 inner join  `portal_products(main category)`main  on
 sub.product_id=main.product_id 
 where sub.product_id=35;

select sub.sub_product_image_path, sub.sub_product_id 
from `portal_products(sub category)` sub , 
inner join `portal_products(main category)`main  on sub.product_id=main.product_id ;

union  all

select sub.sub_product_image_path, sub.sub_product_id 
from `portal_products(sub category)` sub  
where sub.product_id=35