I have a table student like this
id | name | zip
1 | abc | 1234
2 | xyz | 4321
3 | asd | 1234
I want to get all records but zip code should not be repeated. So In case of above table records, record No 1 and 2 should be fetched. Record No. 3 will not be fetched because it has a zip code which is already in record No. 1
SELECT DISTINCT fieldName FROM tableName;
The following query will only select distinct 'zip' field.
SELECT DISTINCT zip FROM student;
SELECT * FROM tableName GROUP BY fieldName;
The following query will select all fields along with distinct zip field.
SELECT * FROM student GROUP BY zip;
TRY
SELECT DISTINCT(zip),id,name FROM student;
OR
SELECT * FROM student GROUP BY zip;
Altough in MySQL you can get away with:
SELECT *
FROM student
GROUP BY zip
I would choose:
SELECT *
FROM student t
JOIN
( SELECT MIN(id) AS minid
FROM student
GROUP BY zip
) AS grp
ON grp.minid = t.id
Since presumably the other columns are of some interest....
SELECT y.*
FROM yourTable y,
(SELECT MIN(y2.id)
FROM yourTable y2
GROUP BY y2.zip) ilv
WHERE ilv.id=y.id;
(or you could use the max-concat trick)
update
Oracle have now removed the max concat trick from the linked page - but it is described elsewhere on the internet
Try Using
Select Distinct(zip),id,name group by zip;
Is there any problem if I use as this below?
select distinct zip,name,id from student;
select id, name, distinct(zip) from student;
Related
I have a table like this:
name |id | state
name1 12 4
name1 12 4
name2 33 3
name2 33 4
...
I want to select every name and id from table where state is only 4, that means name1 is correct, because it only has two records with state 4 and nothing more. Meanwhile name2 is wrong, because it has record with state 4 and record with state 3.
You can use aggregation as shown below:
SELECT name, id
FROM your_table
GROUP BY name, id
HAVING SUM(state<>4)=0;
See a Demo on SQL Fiddle.
select name, id from mytable where id not in
(select distinct id from mytable where state <> 4)
you might need 2 sub queries .
select with group by name were state 4
select with group by name
compare the count if the count is same then select it
example : select name , count (name) from table where state = 4 as T1
select name , count (name) from table as T2
select T1.name from T1 and T2 where T2.count = T1.count
You can use not exists like this:
select distinct name, id
from table1 a
where not exists (select *
from table1 b
where a.id=b.id and state<>4)
In a more general case you can use count distinct (with not exists or with a join):
select distinct name, id
from table1 a
where not exists (
select *
from table1 b
where a.id=b.id
group by id
HAVING count(distinct state)>1)
I have student table
id | name | zip
1 | abc | 1234
2 | xyz | 4321
3 | cde | 1234
And i want to only display unique zip code which is 4321. I don't want to display the 1 and 3 record number. So, how can i display the unique record only?
Thanks In Advance.
The following query will give you all zip codes which don't appear in duplicate:
SELECT zip
FROM yourTable
GROUP BY zip
HAVING COUNT(*) = 1
If you want to also get the full records then you can use the above as a subquery to filter the original table:
SELECT *
FROM yourTable t1
INNER JOIN
(
SELECT zip
FROM yourTable
GROUP BY zip
HAVING COUNT(*) = 1
) t2
ON t1.zip = t2.zip
or this:
SELECT *
FROM yourTable
WHERE zip IN
(
SELECT zip
FROM yourTable
GROUP BY zip
HAVING COUNT(*) = 1
)
This will also work
select
id, name, zip
from
(select
id, name, zip, count(zip) as countZip
from
student
group by zip) as subq
where
countZip = '1'
There is a DISTINCT modifier that forces a select to show only one value for a column that may appear several times. In your case it would be:
SELECT DISTINCT ZIP
FROM ...
Is there any way to get the inverse of a group by statement in mysql? My use case is to delete all duplicates.
Say my table looks like this:
ID | columnA | ...
1 | A
2 | A
3 | A
4 | B
5 | B
6 | C
I want my result set to look like this:
ID | columnA | ...
2 | A
3 | A
5 | B
(Essentially this finds all duplicates leaving one behind. Could be used to purge all duplicate records down to 1, or to perform other analysis later).
One way is to take all but the first id for each value of ColumnA:
select t.*
from t
where t.id > (select min(t2.id) from t t2 where t2.columnA = t.columnA);
Your result seems
select max(id), columnA group by columnA
This should perform a lot better then inner select based queries.
SELECT
*
FROM
TABLE
QUALIFY
RANK() OVER (partition by columnA order by ID ASC ) = 1
EDIT : This apparently wont work in MySQL. Guess the only answer is to by a oracle license - or use another answer. ;)
I realized my own solution based on #scaisEdge response before he edited it. In need the opposite of my group by, so using a subquery:
SELECT * FROM mytable WHERE ID NOT IN (SELECT ID FROM mytable GROUP BY columnA);
I am confident this will help.
create table test.temptable select distinct * from YourTable;
truncate YourTable;
insert into YourTable select * from test.temptable ;
I have duplicate data on my table as described bellow.
no name adrress
1 Joe No.3
2 Joe No.2
3 Joe No.1
4 Anna No.4
5 Anna No.5
6 Ali No.6
I want to show only the first item from duplicate data like bellow.
no name address
1 Joe No.3
2 Anna No.4
If you mean to find the duplicate only, this one similar to your question here
for your case will be like this
SELECT x.*
FROM new_table x
JOIN
( SELECT name
, MIN(id) as min_id , COUNT(id) as count_id
FROM new_table
GROUP
BY name
) y
ON y.name = x.name
AND y.min_id = x.id
AND y.count_id > 1
ORDER
BY id;
hope that answer your question.
There could be lot of answers to this question see which one fits your requirements:
Select * from tablename where no=1;
Select * from tablename where adrress LIKE "%3%";
Select * from tablename ORDER BY no LIMIT 1;
You can use this query for selecting particular row in the table
select * from yourtablename WHERE primarykeyfield=" ";
Try this:
mysql_query("select * from $table where id='1';");
I have two tables with one column each, containing names.
Names can have duplicates. One name can be found on every table or only in one.
I want to make an query that count duplicates, for each name in every table an list these values like this:
| name | table1 | table2 |
| john | 12 | 23 |
| mark | 2 | 5 |
| mary | | 10 |
| luke | 4 | |
I tried different strategies using UNION but no luck.
Thanks in advance!!!
SELECT DISTINCT t1.name, t1.cnt1, t2.cnt2
FROM
(SELECT name,count(name) as cnt1 FROM table1 GROUP BY name) t1
LEFT JOIN
(SELECT name,count(name) as cnt2 FROM table2 GROUP BY name) t2
ON t1.name = t2.name
UNION
SELECT DISTINCT t2.name, t1.cnt1, t2.cnt2
FROM
(SELECT name,count(name) as cnt1 FROM table1 GROUP BY name) t1
RIGHT JOIN
(SELECT name,count(name) as cnt2 FROM table2 GROUP BY name) t2
ON t1.name = t2.name
Here's a simpler solution:
You can UNION the names from the two tables together, manually differentiating their origin tables with a tbl column.
Then it's just a simple GROUP BY with conditional aggregation using the differentiating column:
SELECT a.name,
NULLIF(COUNT(CASE a.tbl WHEN 1 THEN 1 END), 0) AS table1,
NULLIF(COUNT(CASE a.tbl WHEN 2 THEN 1 END), 0) AS table2
FROM
(
SELECT name, 1 AS tbl FROM table1 UNION ALL
SELECT name, 2 FROM table2
) a
GROUP BY a.name
In accordance with your desired result-set, we NULL the count value if it turns out to be 0.
SQLFiddle Demo
SELECT SUM(res.cn), name
FROM
(
SELECT name, count(name) as cn from table1 GROUP BY name HAVING count(name) > 1
UNION ALL
SELECT name, count(name) as cn from table2 GROUP BY name HAVING count(name)>1
) as res
GROUP BY nam
e
Try the above :) I made a fiddle for you to test it:
http://sqlfiddle.com/#!3/796b2/3
It has a few double names in each table and will show you which names have doubles and then print them. The names that only appear once are not shown (acheived by the HAVING clause)
After some reading i don't think that it's posibil what i want to do. This situation ca be solved with pivot table in excel or libreoffice.
In fact this is method that i used, combined with some sql stataments to count occurence of names and export as CSV.
UNION definitetly not work. Some chance are with join, but not shure.
I found a post that discusses the same problem as mine.
MySQL - Rows to Columns