MySQL：按符号分组，但保留所有最高目标值行

Question

The below data is just an abstract of my original data ,formed by 'join' of four tables. The requirement is ;

data :
 symbol  target  analyst
    a       1690    peas
    a       1230    tomato
    a       1235    papaya
    a       1230    papaya
    a       1690    apple 
    b       1450    bean
    b       1914    potato
    b       1540    tomato
    b       1797    papaya
    b       1880    apple 
    b       2000    turnips
    c       1550    bean
    c       1588    onion
    c       1588    onion
    c       1588    potato
    c       1463    soya
    c       1130    tomato    

  required : symbol target analyst a 1690 peas a 1690 apple b 2000 turnips c 1588 onion c 1588 potato 

ie for each symbol in the table,the rows for max(target) for each unique analyst has to be displayed . Tried using combination of 'max(target)' and 'group by symbol' , which displays only one maximum target row . A part of the code used to form data is ;

SELECT 
     a.symbol, c.target, c.analyst 
FROM table1 a
     LEFT JOIN table2 b 
         ON a.symbol = b.symbol 
     LEFT JOIN table3 c 
         ON a.symbol LIKE CONCAT('%', c.symbol , '%')
     LEFT JOIN table4 d 
         ON a.symbol = d.symbol;

Answer 1

To get the desired out put you can do self join

select distinct a.*
from demo a 
left join demo b on a.symbol = b.symbol
                 and a.target < b.target
where b.symbol is null

Demo

Answer 2

You can use a join against a select that get the max target for each symbol:

SELECT
    a.symbol,
    a.target,
    a.analyst
FROM data a
LEFT JOIN (SELECT b.symbol,MAX(b.target) as `maxval` FROM data b GROUP BY b.symbol) b
ON b.symbol = a.symbol AND b.`maxval` = a.target
ORDER BY a.symbol,a.target,a.analyst