mysql - INSERT INTO with SELECT and rand() confusing variables -


i trying make part of table copied table b:

@t1 := 1 insert b select x, y, (@t1:=@t1+1) z=1 order rand() limit 10

what wanted in table b (third column) values 1 10, making values 12, 124, 45 etc... wonder if first variables , order rand() values never exceeds numbers of rows in table a.

is there other way 10 random rows b , mark them in third column (sort column) 1 10? in 1 mysql statement, know how 10 inserts ;-)

sort first, calculate row number on rows returned order by/limit:

set @t1 := 1;  insert b select x, y, (@t1:=@t1+1) (   select x, y     z=1   order rand()   limit 10) ten_rows

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