In spark SQL, date is used to display the day of the week according to the year, month and day_ format(date,‘u‘)

====SparkSQL in 
select date_format(now(),'u')
select date_format('2022-07-02','u')
 result ==》6
 
select date_format('2022-07-03','u')
 result ==》7
 
select date_format('2022-07-04','u')
 result ==》1
 
select date_format('2022-07-05','u')
 result ==》2
 
select date_format('2022-07-06','u')
 result ==》3
 
select date_format('2022-07-07','u')
 result ==》4
 
select date_format('2022-07-08','u')
 result ==》5

Be careful ：

select date_format('2022-07-02','u')
result ==》6

date_format（date,'u'） function hivesql and sparksql support , however mysql and doris as well as prestosql Neither support

example ：

select instr("abc", "b");
 result ==》2

select date_format('2022-07-22','u')
 result ==》5

select instr('1-2-3-4-5-6-7',date_format('2022-07-22', 'u'))
 result ==》9

select instr('1-2-3-4-5-6-7',date_format('2022-07-22', 'u'))>0
 result ==》true