我试图通过按雇员ID连接两个表来执行sql查询，这两个表的平衡期为2-12，总和为hrs和grs mtd

你看起来像这样吗

SELECT I.EMPLID, 
       I.NAME, 
       I.CAG_COMPANY_DESCR, 
       I.LOCATION_NAME, 
       I.JOBCODE, 
       I.WORKERS_COMP_CD, 
       J.ERNCD, 
       J.BALANCE_QTR, 
       J.BALANCE_PERIOD, 
       J.HRS_MTD, 
       J.GRS_MTD      
FROM PS_CAG_EMPLOYEES I, PS_EARNINGS_BAL J 
WHERE J.EMPLID = I.EMPLID 
  AND J.ERNCD = '103' 
  AND J.BALANCE_YEAR = '2016' 
  AND J.BALANCE_ID = 'CY' 
  AND J.BALANCE_PERIOD ='12' 

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向我们显示数据库模式、示例数据和预期输出。请阅读，这里是学习如何提高问题质量和获得更好答案的好地方。推广使用explict

JOIN

sintaxis，Aaron Bertrand为此写了一篇很好的文章。减去1是因为试图将整个问题塞进标题，而不是将问题放在实际问题的文本中。mysql和ms sql server是两种不同的产品。你用哪一种？这个问题怎么了？

SELECT I.EMPLID, 
       I.NAME, 
       I.CAG_COMPANY_DESCR, 
       I.LOCATION_NAME, 
       I.JOBCODE, 
       I.WORKERS_COMP_CD, 
       J.ERNCD, 
       J.BALANCE_QTR, 
       J.BALANCE_PERIOD, 
       HRS_MTD = SUM(J.HRS_MTD), 
       GRS_MTD = SUM(J.GRS_MTD)      
FROM PS_CAG_EMPLOYEES I
INNER JOIN PS_EARNINGS_BAL J 
ON J.EMPLID = I.EMPLID 
  AND J.ERNCD = '103' 
  AND J.BALANCE_YEAR = '2016' 
  AND J.BALANCE_ID = 'CY' 
  AND J.BALANCE_PERIOD ='12' 
GROUP BY 
    I.EMPLID, 
    I.NAME, 
    I.CAG_COMPANY_DESCR, 
    I.LOCATION_NAME, 
    I.JOBCODE, 
    I.WORKERS_COMP_CD, 
    J.ERNCD, 
    J.BALANCE_QTR, 
    J.BALANCE_PERIOD