Question

我在我的SQL查询中集成NOT EXISTS时遇到问题。让我详细解释一下这个问题我有四个表：branch_details，transactions，branch_order_relation和branch_pincode_relation。

这是我的SQL查询

   private static final String SELECT_ORDERS_BY_BRANCH = 
"select transaction_id,source_id,destination_id 
from transactions,branch_pincode_relation,branch_details,branch_order_relation 
where branch_details.branch_email = ? 
and branch_details.branch_id = branch_pincode_relation.branch_id 
and branch_pincode_relation.origin_pincode = transactions.start_pin 
and transactions.parent_transaction_id IS NOT NULL 
and transactions.order_status = "+JiffieConstants.PAYMENT_SUCCESS;

有一些transaction_id of transactions表存在于branch_order_relation中（作为order_id）。因此，如果transaction_id存在于branch_order_relation中，我们就不应该选择它。否则我们需要选择它。任何人都可以在上面的SQL查询中集成它。我也尝试过google但是却无法提出解决方案

Answer 1

我将查询修改为

private static final String SELECT_ORDERS_BY_BRANCH =＆＃34; select transaction_id，source_id，destination_id from transactions，branch_pincode_relation，branch_details where branch_details.branch_email =？和branch_details.branch_id = branch_pincode_relation.branch_id和branch_pincode_relation.origin_pincode = transactions.start_pin和transactions.parent_transaction_id IS NOT NULL且transactions.order_status =＆＃34; + JiffieConstants.PAYMENT_SUCCESS +＆＃34;和NOT EXISTS（从branch_order_relation中选择null，其中branch_order_relation.order_id = transactions.transaction_id）＆＃34 ;;

及其工作。谢谢！

Answer 2

在transactions和branch_order_relation上使用左外连接，并添加where branch_order_relation.order_id is null子句。

这将选择不在branch_order_relation中的交易，见下文

select transaction_id,source_id,destination_id 
from transactions 
left outer join branch_order_relation on transactions.transaction_id = branch_order_relation.order_id
 where branch_order_relation.order_id is null

然后加入其他表格，并添加你的where子句

SQL Not Exists查询

2 个答案: