select
mch_nm,
sum(trx_amt) mch_total_amt
from cmb_usr_trx_rcd 
group by mch_nm
having sum(trx_amt) > 10*(select avg(trx_amt)
 from cmb_usr_trx_rcd 
							)

select * 
from cmb_usr_trx_rcd 
where usr_id not in (select usr_id
from cmb_usr_trx_rcd
where mch_nm = '肯德基')

SELECT *
FROM cmb_usr_trx_rcd
WHERE usr_id IN (
    SELECT DISTINCT usr_id
    FROM cmb_usr_trx_rcd
    WHERE mch_nm = '肯德基'
)
ORDER BY usr_id, trx_time;

select * from cmb_usr_trx_rcd
where mch_nm = '肯德基'

select * 
from cmb_usr_trx_rcd 
where trx_amt > (select avg(trx_amt)
from cmb_usr_trx_rcd )

select
*,
(select avg(trx_amt)
from cmb_usr_trx_rcd) avg_trx_amt
from cmb_usr_trx_rcd
where usr_id=5201314520

select 
usr_id,
sum(trx_amt) total_amt,
(select avg(trx_amt)
from cmb_usr_trx_rcd) platform_avg_amt
from cmb_usr_trx_rcd 
group by usr_id

select
replace(singer_name,' ','') new_singer_name
 from singer_info

select 
replace(song_name,'人','狗') new_song_name
from song_info
where song_name like '%人%'

select 
replace(song_name,'人','狗') new_song_name
from song_info

select 
singer_name,
(case when singer_name like '__e%' then 1
when singer_name like '_e%' then 1
when singer_name like 'e%' then 1
else 0 end) if_e_lessthan3
from singer_info

select length(singer_name),count(singer_id) from singer_info 
group by length(singer_name)

select count(singer_name) from singer_info 
group by length(singer_name)

select
singer_name,
char_length(singer_name)
from singer_info

select 
char_length(singer_name)
from singer_info

select 
length(singer_name)
from singer_info

select 
upper(singer_name)
from singer_info

SELECT *
FROM numbers_for_fun
WHERE
    (a = 0 AND (
        (b = 0 AND c < 0) 
        OR (b != 0 AND (
            (b > 0 AND c < 0) 
            OR (b < 0)        
        ))
    ))
    OR
    (a != 0 AND (
        (a > 0 AND (c < 0 OR (b < 0 AND 4*a*c < b*b)))
        OR
        (a < 0)
    ));

select 
    * 
from
    numbers_for_fun
where
    (a=0 and b>=0 and c <=0)
    or (a<0 and 
       (
           (b>=0 and c<=0)
       or (b<0 and c<=(b*b/4/a))
       )
       )

select * from numbers_for_fun 
where (a<0 and c<=0)
or (a=0 and b>=0 and c<=0)