Question at position 51 We can calculate the cumulative sum for each date using the following SQL statement: SELECT t1.date, t1.precip AS 'daily precip', SUM(t2.precip) AS 'cum. precip' FROM rainfall AS t1 INNER JOIN rainfall AS t2 ON t2.date = t1.date GROUP BY t1.date ORDER BY t1.date;TrueFalse

Question

Question at position 51 We can calculate the cumulative sum for each date using the following SQL statement: SELECT t1.date, t1.precip AS 'daily precip', SUM(t2.precip) AS 'cum. precip' FROM rainfall AS t1 INNER JOIN rainfall AS t2 ON t2.date >= t1.date GROUP BY t1.date ORDER BY t1.date;TrueFalse

BlackTom AI · Accepted Answer

The question presents a SQL statement and asks to determine whether the statement is True or False.
Option 1: True. The given query attempts to compute a daily precip and a cumulative precip by joining the rainfall table to itself with t2.date >= t1.date, then grouping by t1.date. This logic yields the sum of precip for dates from t1.date forward (i.e., from the current date to the end), not the running total up to and including t1.date. Therefore, it does not produce a true cumulative sum as typically defined, which should accumulate from the earliest date up to the current date. This makes the statement described by Option 1 incorrect.
Option 2: False. Since the reasoning in Option 1 identifies that the join condition and aggregation produce a sum over future dates rather than a running total up to each date, the statement in Option 1 is not correct. The correct assessment is that the described SQL does not correctly compute a cumulative sum per date, so labeling the statement as True would be inaccurate. The reasoning aligns with the idea that the approach shown would misrepresent the direction of accumulation and would not yield the expected cumulative precipitation up to each date.
In summary, Option 1 is inconsistent with the standard definition of a cumulative sum for each date due to the join condition t2.date >= t1.date and the resulting aggregation, while Option 2 correctly identifies this inconsistency.

Question at position 51 We can calculate the cumulative sum for each date using the following SQL statement: SELECT t1.date, t1.precip AS 'daily precip', SUM(t2.precip) AS 'cum. precip' FROM rainfall AS t1 INNER JOIN rainfall AS t2 ON t2.date >= t1.date GROUP BY t1.date ORDER BY t1.date;TrueFalse

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