how to find repeated value and count in mysql -


i have table 3 columns, how find value if appears next 3 times i.e 1st trnas_value appears in next 3 consecutive times (repeaded 4 times) , 2nd , 6th rows repeated same.date column sorted a_z

date               tran_val                name 23mar                22                    mark 24mar                22                    mark 25mar                22                    mark 26mar                22                    mark 27mar                22                    mark 28jan                99                    john 29jan                99                    john 30jan                99                    john 31jan                99                    john

output

name     trans_value        consecutive_count mark       22                   2 john       99                   1

we have code not giving above output.. 

select name,          tran_val,          max(cnt - 3) consecutive_count (     select date,              tran_val,              name,              @cnt:=if(@tran_val=tran_val , @name=name, @cnt + 1, 1) cnt,             @tran_val:=tran_val,             @name:=name     some_table     cross join (select @cnt:=0, @tran_val:=0, @name:='') sub0     order `date` ) sub1 group name,          tran_val

any modification in above code desired output.thanks

try this:

select `tran_val`, `name`, count(*) - 3 (   select `date`, `tran_val`, `name`, rn - seq grp   (     select `date`, `tran_val`, `name`,            @rn := @rn + 1 rn,            @seq := if(@name = `name` , @val = `tran_val`, @seq+1, 1) seq,            @name := name,            @val := tran_val     mytable     cross join (select @rn := 0, @seq := 0, @name = '', @val = 0) vars     order `date`) t ) s group `tran_val`, `name`, grp having count(*) > 3

you need two separate variable enumerate sequences:

  • @rn enumerates consecutive table rows
  • @seq enumerates consecutive table rows having same name, tran_val values.

the difference between these 2 variables, i.e. @rn - @seq, identifies islands of consecutive table rows having same name, tran_val values.

edit: added having clause query filter out islands having population of 3 or less consecutive rows.

demo here


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