如何在mysql中使用selectcase

以下是MSSQL语法，如何将其转换为mysql

    SELECT          
    _nextBillingDate = UB.NextBillingDate,
    _billingFrequency = (CASE IFNULL(UB.BillingFrequency,0) WHEN 0 THEN
     _defaultBillingFrequency ELSE UB.BillingFrequency END),
    _isCompletelyCreditBilled = (CASE WHEN PO.ChargeAmount > 0 THEN 0 ELSE 1 END),
    _ownerId = PO.OwnerId   
    FROM PaymentOrder PO
    INNER JOIN UserBillingInfo UB ON PO.OwnerId = UB.OwnerId
    WHERE PO.Id = _paymentOrderId

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在过程中，mysql使用

select cols into vars from…

样式语法，因此请尝试以下方法：

-- DECLARE variables at the top of your procedure

SELECT
    UB.NextBillingDate,
    CASE IFNULL(UB.BillingFrequency,0) WHEN 0 THEN _defaultBillingFrequency ELSE UB.BillingFrequency END,
    CASE WHEN PO.ChargeAmount > 0 THEN 0 ELSE 1 END,
    PO.OwnerId
INTO
    _nextBillingDate, _billingFrequency, _isCompletelyCreditBilled, _ownerId 
FROM PaymentOrder PO
INNER JOIN UserBillingInfo UB ON PO.OwnerId = UB.OwnerId
WHERE PO.Id = _paymentOrderId

mysql中的“选择*进入” mysql中不允许使用“select*into”。下面是一个绕过此限制的示例：

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创建表newtable SELECT*FROM oldtable

阅读MSSQL和MySQL之间的一些差异。您可以下载可用于将MSSQL语句转换为MySQL语句的应用程序。选中mysql中的“select*into”，mysql中不允许“select*into”。下面是一个绕过此限制的示例：创建表newtable从oldtable选择*