I cannot find the answer to the abovementioned problem in the title.
I need to select all rows that have the identical ID and all other column values must also be identical as well. This table consists of 20 columns.
Any suggestion would be much appreciated! Many thanks.
How about this
select id, name, ...other fields
from my_table
where id in (
Select id, count(id)
from my_table
group by id, name, ...other fields
having count(id) > 1
)
Change group by and where conditions accordingly
Related
Does anyone know the sql to pull 4 rows from the following table which contains 8 rows?
Just want one row for each arbitrary person.
The real data will be thousands of records so it must be generic and use only the ID's not the names.
table
You seem to have a symmetric relationship. So, you can do:
select t.*
from t
where t.id < t.pid;
select
ID,
FName,
LName
from your_table
union
select
PID,
PFName,
PLName
from your_table
order by 3, 2, 1
I was asked this question during an interview for a Junior Oracle Developer position, the interviewer admitted it was a tough one:
Write a query/queries to check if the table 'employees_hist' is an exact copy of the table 'employees'. Any ideas how to go about this?
EDIT: Consider that tables can have duplicate records so a simple MINUS will not work in this case.
EXAMPLE
EMPLOYEES
NAME
--------
Jack Crack
Jack Crack
Jill Hill
These two would not be identical.
EMPLOYEES_HIST
NAME
--------
Jack Crack
Jill Hill
Jill Hill
If the tables have the same columns, you can use this; this will return no rows if the rows in both tables are identical:
(
select * from test_data_01
minus
select * from test_data_02
)
union
(
select * from test_data_02
minus
select * from test_data_01
);
Identical regarding what? Metadata or the actual table data too?
Anyway, use MINUS.
select * from table_1
MINUS
select * from table_2
So, if the two tables are really identical, i.e. the metadata and the actual data, it would return no rows. Else, it would prove that the data is different.
If, you receive an error, it would mean the metadata itself is different.
Update If the data is not same, and that one of the table has duplicates.
Just select the unique records from one of the table, and simply apply MINUS against the other table.
One possible solution, which caters for duplicates, is to create a subquery which does a UNION on the two tables, and includes the number of duplicates contained within each table by grouping on all the columns. The outer query can then group on all the columns, including the row count column. If the table match, there should be no rows returned:
create table employees (name varchar2(100));
create table employees_hist (name varchar2(100));
insert into employees values ('Jack Crack');
insert into employees values ('Jack Crack');
insert into employees values ('Jill Hill');
insert into employees_hist values ('Jack Crack');
insert into employees_hist values ('Jill Hill');
insert into employees_hist values ('Jill Hill');
with both_tables as
(select name, count(*) as row_count
from employees
group by name
union all
select name, count(*) as row_count
from employees_hist
group by name)
select name, row_count from both_tables
group by name, row_count having count(*) <> 2;
gives you:
Name Row_count
Jack Crack 1
Jack Crack 2
Jill Hill 1
Jill Hill 2
This tells you that both names appear once in one table and twice in the other, and therefore the tables don't match.
select name, count(*) n from EMPLOYEES group by name
minus
select name, count(*) n from EMPLOYEES_HIST group by name
union all (
select name, count(*) n from EMPLOYEES_HIST group by name
minus
select name, count(*) n from EMPLOYEES group by name)
You could merge the two tables and then subtract one of the tables from the result. If the result of the subtraction is an empty table then you know that the the tables must be the same since merge had no effect (every row and column were effectively the same)
How do I merge two tables with different column number while removing duplicates?
That link provides a good way to merge the two tables without duplicates without knowing what the columns are.
Ensure the rows are unique by adding a pseudo column
WITH t1 AS
(SELECT <All_Columns>
, row_number() OVER
(PARTITION BY <All_Columns>
ORDER BY <All_Columns>) row_num
FROM employees)
, t2 AS
(SELECT <All_Columns>
, row_number() OVER
(PARTITION BY <All_Columns>
ORDER BY <All_Columns>) row_num
FROM employees_hist)
(SELECT *
FROM t1
MINUS
SELECT *
FROM t2
UNION ALL
(SELECT *
FROM t1
MINUS
SELECT *
FROM t2)
Use row_number to make sure there are no duplicate rows. Now you can use minus and if there are no results, the tables are identical.
SELECT ROW_NUMBER() OVER (Order By Name), *
FROM tab1
MINUS
SELECT ROW_NUMBER() OVER (Order By Name), *
FROM tab2
I have two tables with data. Both tables have a CUSTOMER_ID column (which is numeric). I am trying to get a list of all the unique values for CUSTOMER_ID and know whether or not the CUSTOMER_ID exists in both tables or just one (and which one).
I can easily get a list of the unique CUSTOMER_ID:
SELECT tblOne.CUSTOMER_ID
FROM tblOne.CUSTOMER_ID
UNION
SELECT tblTwo.CUSTOMER_ID
FROM tblTwo.CUSTOMER_ID
I can't do just add an identifier column to the SELECT statemtn (like: SELECT tblOne.CUSTOMER_ID, "Table1" AS DataSource) because then the records wouldn't be unique and it will get both sets of data.
I feel I need to add it somewhere else in this query but am not sure how.
Edit for clarity:
For the union query output I need an additional column that can tell me if the unique value I am seeing exists in: (1) both tables, (2) table one, or (3) table two.
If the CUSTOMER_ID appears in both tables then we'll have to arbitrarily pick which table to call the source. The following query uses "tblOne" as the [SourceTable] in that case:
SELECT
CUSTOMER_ID,
MIN(Source) AS SourceTable,
COUNT(*) AS TableCount
FROM
(
SELECT DISTINCT
CUSTOMER_ID,
"tblOne" AS Source
FROM tblOne
UNION ALL
SELECT DISTINCT
CUSTOMER_ID,
"tblTwo" AS Source
FROM tblTwo
)
GROUP BY CUSTOMER_ID
Gord Thompson's answer is correct. But, it is not necessary to do a distinct in the subqueries. And, you can return a single column with the information you are looking for:
select customer_id,
iif(min(which) = max(which), min(which), "both") as DataSource
from (select customer_id, "tblone" as which
from tblOne
UNION ALL
select customer_id, "tbltwo" as which
from tblTwo
) t
group by customer_id
We could add an identifier column with the integer data type and then do an outer query:
SELECT
CUSTOMER_ID,
sum(Table)
FROM
(
SELECT
DISTINCT CUSTOMER_ID,
1 AS Table
FROM tblOne
UNION
SELECT
DISTINCT CUSTOMER_ID,
2 AS Table
FROM tblTwo
)
GROUP BY CUSTOMER_ID`
So if the "sum is 1" then it comes from tablOne and if it is 2 then it comes from tableTwo an if it is 3 then it exists in both
If you want to add a 3rd table in the union then give it a value of 4 so that you should have a unique sum for each combination
Can i select all rows that have same column value (for example SSN field) but display them all separably. ?
I've searched for this answer but they all have "count(*) and group by" section that demands the rows to be exactly same.
Try This:
SELECT A, B FROM MyTable
WHERE A IN
(
SELECT A FROM MyTable GROUP BY A HAVING COUNT(*)>1
)
I have done with SQL server. But hope this is what you need
Here is another approach, which only references the table once, using an analytic function instead of a subquery to get the duplicate counts It might be faster; it also might not, depending on the particular data.
SELECT * FROM (
SELECT col1, col2, col3, ssn, COUNT(*) OVER (PARTITION BY ssn) ssn_dup_count
)
WHERE ssn_dup_count > 1
ORDER BY ssn_dup_count DESC
SELECT
*
FROM
MyTable
WHERE
EXISTS
(
SELECT
NULL
FROM
MyTable MT
WHERE
MyTable.SameColumnName = MT.SameColumnName
AND MyTable.DifferentColumnName <> MT.DifferentColumnName)
This will fetch the required data and show them in order so that we can see the grouped data together.
SELECT * FROM TABLENAME
WHERE SSN IN
(
SELECT SSN FROM TABLENAMEGROUP BY SSN HAVING COUNT(SSN)>1
)
ORDER BY SSN
Here SSN is the column names fro which similar value check is done.
Ok so I have a table in which ONE of the columns have a FEW REPEATING records.
My task is to select the REPEATING records with all attributes.
CustID FN LN DOB City State
the DOB has some repeating values which I need to select from the whole table and list all columns of all records that are same within the DOB field..
My try...
Select DOB, COUNT(DOB) As 'SameDOB' from Table1
group by DOB
HAVING (COUNT(DOB) > 1)
This only returns two columns and one row 1st column is the DOB column that occurs more than once and the 2nd column gives count on how many.
I need to figure out a way to list all attributes not just these two...
Please guide me in the right direction.
I think a more general solution is to use windows functions:
select *
from (select *, count(*) over (partition by dob) as NumDOB
from table
) t
where numDOB > 1
The reason this is more general is because it is easy to change to duplicates across two or more columns.
Select *
FROM Table1 T
WHERE T.DOB IN( Select I.DOB
FROM Table1 I
GROUP BY I.DOB
HAVING COUNT(I.DOB) > 1)
Try joining with a subquery, which will also allow you to see the count
select t.*, a.SameDOB from Table1 t
join (
Select DOB, COUNT(DOB) As 'SameDOB' from Table1
group by DOB
HAVING (COUNT(DOB) > 1)
) a on a.dob = t.dob
select *
from table1, (select count(*) from table1) as cnt