SQL: How can I return the highest ranking record of similar records, based on one column value?

Question

This seems like it should be easier than I\'m finding it. I have a table that contains both first and last names (specified by a type ID) and a frequency of how common the name

Answer 1

If I understand what you're wanting...

This will get you the First Names:

SELECT *
FROM [NameTable]
WHERE FrequencyPercent > 1.0
    AND NameType = 1
ORDER BY FrequencyPercent

Answer 2

If you want top 2 for both first and last name, you can do UNION ALL.

select name 
FROM table
where Nametype = 1
order by FrequencyPercent desc
limit 2
UNION ALL
select name 
from table
where nametype = 2
order by FrequencyPercent desc
limit2

Answer 3

If I understand correctly you're looking for first names when the frequency is higher than the frequency as same name as last name

This works for first names. You just need to reverse it for last names

CREATE Table YourTable
(
NameType int,
name varchar(20),
FrequencyPercent decimal(12,4)
)

INSERT INTO  YourTable
VALUES (1 ,'John', 3.267),
(1 , 'Thomas',      1.987),
(1 , 'Wilson',      0.945),
(2 , 'Smith',       4.528),
(2 ,  'Wilson',      2.221),
(2 ,   'Thomas',      0.437)

SELECT firstNames.name
FROM
      YourTable firstNames 
LEFT JOIN YourTable  lastNames 
 ON firstnames.Name = lastNames.Name
    AND lastNames.NameType  =2
     and firstnames.FrequencyPercent < lastNames.FrequencyPercent
WHERE firstNames.NameType  =1
      AND
      lastNames.name is null

results in

name
--------------------
John
Thomas
(2 row(s) affected)

Answer 4

Top 5 most common first names:

select Name
  from Names
  where NameType = 1
  order by FrequencyPercent desc
  limit 5;