通过条款分组与最高记录 - MYsql

Question

我编写了以下SQL查询，效果很好

SELECT   
context.data.EventTime as eventTime,
context.device.type as deviceType,
GetRecordPropertyValue(GetArrayElement(context.custom.dimensions, 4), 'MachineName') AS machineName,  
GetRecordPropertyValue(GetArrayElement(context.custom.dimensions, 5), 'UserId') AS userId,
GetRecordPropertyValue(GetArrayElement(context.custom.dimensions, 9), 'UserName') AS userName,
GetRecordPropertyValue(GetArrayElement(context.custom.dimensions, 11), 'remoteIpAddress') AS remoteIpAddress,
GetRecordPropertyValue(GetArrayElement(context.custom.dimensions, 13), 'EventName') AS eventName     
INTO output1
FROM input1

显示以下结果

有没有办法只返回一个顶级记录，我不想只显示多个记录中的第一个记录

Answer 1

SELECT TOP 1 W.LineItems_LineItemID, P.CurrentRate, P.CurrentEffectiveDate 
  FROM WorkOrderLineItems W 
  JOIN PayScaleLoaclJObCodes P ON P.JobCodeID = W.LineItems_LineItemID 
  WHERE P.PayScalesLocal_ID = 29 AND W.WorkOrderCurrent_WorkOrderID = 120420
  AND P.CurrentEffectiveDate <= '2018-05-27' 
  ORDER BY P.CurrentEffectiveDate DESC

SELECT TOP子句用于指定要返回的记录数。对于您的情况，您只需要TOP 1一个。

OR

SELECT W.LineItems_LineItemID, P.CurrentRate, P.CurrentEffectiveDate 
  FROM WorkOrderLineItems W 
  JOIN PayScaleLoaclJObCodes P ON P.JobCodeID = W.LineItems_LineItemID 
  WHERE P.PayScalesLocal_ID = 29 AND W.WorkOrderCurrent_WorkOrderID = 120420
  AND P.CurrentEffectiveDate <= '2018-05-27' 
  ORDER BY P.CurrentEffectiveDate DESC 
  LIMIT 1