在數(shù)據(jù)清洗過程中，可以使用SQL的rank()函數(shù)來對數(shù)據(jù)進行排序和排名，以便更好地理解和分析數(shù)據(jù)。以下是rank()函數(shù)在數(shù)據(jù)清洗中的一些常見應用：
SELECT *
FROM (
SELECT *,
RANK() OVER(PARTITION BY column1, column2 ORDER BY column3) as r
FROM table_name
) AS temp
WHERE r = 1;
SELECT *,
RANK() OVER(PARTITION BY column1 ORDER BY column2) as r
FROM table_name;
SELECT *
FROM (
SELECT *,
RANK() OVER(ORDER BY column1) as r
FROM table_name
) AS temp
WHERE r = 1;
總的來說，rank()函數(shù)在數(shù)據(jù)清洗中可以幫助我們更好地理解數(shù)據(jù)，發(fā)現(xiàn)數(shù)據(jù)中的重復項、分析數(shù)據(jù)的排序和分布情況，以及比較不同數(shù)據(jù)之間的排名情況，從而更好地進行數(shù)據(jù)處理和分析。
