sql - 如何使用条件使用来自单独表的数据更新一个表

Question

这个查询可能非常荒谬，或者我只是有一点错误。我不太确定。但基本上我正在尝试使用 Access 中另一个表中的数据更新一个表。给我带来问题的列是那些设置为“是/否”类型的列，我尝试更新它的数据被设置为“文本”类型，其值为字符串"is"或“否”。

所以我对这个查询的想法，如果可能的话，是将“文本”字段粗略地转换为 1 或 0，具体取决于它们的 Yes 或 No 值。无论如何，足够的背景，这里是查询:

UPDATE Group_Pricing SET 
Contract_Type = (SELECT Contract_Type FROM ContractTypesFinal WHERE ContractTypesFinal.FirstGroup = Group_Pricing.GroupID), 
Hybrid_Retail =  
(SELECT CASE (SELECT RetailSpread FROM ContractTypesFinal WHERE ContractTypesFinal.FirstGroup = Group_Pricing.GroupID)
CASE "Yes"
RetailSpread = 1
CASE "No"
RetailSpread = 0), 
Hybrid_Mail =  
(SELECT CASE (SELECT MailSpread FROM ContractTypesFinal WHERE ContractTypesFinal.FirstGroup = Group_Pricing.GroupID)
CASE "Yes"
MailSpread = 1
CASE "No"
MailSpread = 0),
Hybrid_Specialty =  
(SELECT CASE (SELECT SpecialtySpread FROM ContractTypesFinal WHERE ContractTypesFinal.FirstGroup = Group_Pricing.GroupID)
CASE "Yes"
SpecialtySpread = 1
CASE "No"
SpecialtySpread = 0),
Hybrid_Rebates =  
(SELECT CASE (SELECT Rebates FROM ContractTypesFinal WHERE ContractTypesFinal.FirstGroup = Group_Pricing.GroupID)
CASE "Yes"
Rebates = 1
CASE "No"
Rebates = 0)
WHERE EXISTS (SELECT 1 FROM ContractTypesFinal WHERE ContractTypesFinal.FirstGroup = Group_Pricing.GroupID);

非常感谢任何帮助。如果这是不可能的，就告诉我我是个白痴。谢谢!

Answer 1

MS Access 中不能有 CASE，但可以有 IIf。

UPDATE Group_Pricing SET 
Contract_Type = 
     (SELECT Contract_Type 
      FROM ContractTypesFinal 
      WHERE ContractTypesFinal.FirstGroup = Group_Pricing.GroupID), 
Hybrid_Retail =  
IIf (SELECT RetailSpread 
     FROM ContractTypesFinal 
     WHERE ContractTypesFinal.FirstGroup = Group_Pricing.GroupID)="Yes",1,0)

<...>

请注意 MS Access 中的 YesNo 为 -1 和 0

然而，只说:

UPDATE table1 SET AYesNo=(AText="Yes")

编辑

UPDATE Group_Pricing 
INNER JOIN ContractTypesFinal 
ON Group_Pricing.GroupID = ContractTypesFinal.FirstGroup 
SET Hybrid_Retail = (RetailSpread="Yes")

此 (RetailSpread="Yes")将评估为 True (-1)