Subtract data from the first day vs. the last day of the month in SQL of all months of the year

[pturmel]

This is a duplicate of what you asked two days ago. Keep discussions in one topic, per this forum's rules.

Compare start of month data and end of month data

HI I have a currently query for compares a previous day against a current day, but now I need to compare the start day of the month against the last day of the month. this my currently query: DECLARE @FechaInicial DATE = '2024-01-08'; DECLARE @FechaFinal DATE = '2024-02-08'; SELECT dm.Fecha, SUM(CASE WHEN dm.Linea = 'ELFO_006_Oficinas' THEN dm.Dato - ISNULL( dp.Dato, 0) ELSE 0 END) AS ELFO_006_Oficinas_Diferencia, SUM(CASE WHEN dm.Linea = 'ELFO_007_Rim' THEN dm.Dato - ISNULL( …