SAP Business One query to compare sales turnover between two periods

 SELECT 

    YEAR(T1.DocDate) AS 'Year',

    MONTH(T1.DocDate) AS 'Month',

    SUM(CASE WHEN T1.DocDate BETWEEN '2021-01-01' AND '2021-03-31' THEN T1.LineTotal ELSE 0 END) AS 'Sales Period 1',

    SUM(CASE WHEN T1.DocDate BETWEEN '2021-04-01' AND '2021-06-30' THEN T1.LineTotal ELSE 0 END) AS 'Sales Period 2'

FROM 

    OINV T1

WHERE 

    T1.DocStatus = 'C' 

    AND T1.DocDate BETWEEN '2021-01-01' AND '2021-06-30'

GROUP BY 

    YEAR(T1.DocDate), 

    MONTH(T1.DocDate)