Performing a subquery using values from a column in Oracle - sql

I'm trying to create a calculated column in SQL. Basically I need to get a set of distinct dates and determine how many customers there are in the population on that particular date. The result should be something like:
Date______| Customers
2016-01-01 | 1
2016-01-01 | 2
2016-01-05 | 3
2016-02-09 | 4
etc.
I created a sample database & data (using MySQL as I don't have permission to create tables in our Oracle dbs) with the following script:
create database customer_example;
use customer_example;
create table customers (
customer_id int not null primary key,
customer_name varchar(255) not null,
term_date DATE);
create table employee (
employee_id int not null primary key,
employee_name varchar(255) not null);
create table cust_emp (
ce_id int not null AUTO_INCREMENT,
emp_id int not null,
cust_id int not null,
start_date date,
end_date date,
deleted_yn boolean,
primary key (emp_id, cust_id, ce_id),
foreign key (cust_id) references customers(customer_id),
foreign key (emp_id) references employee(employee_id));
insert into customers (customer_id, customer_name)
values (1, 'Bobby Tables'), (2, 'Grover Cleveland'), (3, 'Chester Arthur'), (4, 'Jan Bush'), (5, 'Emanuel Porter'), (6, 'Darren King'), (7, 'Casey Mcguire'), (8, 'Robin Simpson'), (9, 'Robin Tables'), (10, 'Mitchell Arnold');
insert into customers (customer_id, customer_name, term_date)
values (11, 'Terrell Graves', '2017-01-01'), (12, 'Richard Wagner', '2016-10-31'), (13, 'Glenn Saunders', '2016-11-19'), (14, 'Bruce Irvin', '2016-03-11'), (15, 'Glenn Perry','2016-06-06'), (16, 'Hazel Freeman', '2016-07-10'),
(17, 'Martin Freeman', '2016-02-11'), (18, 'Morgan Freeman', '2017-02-01'), (19, 'Dirk Drake', '2017-01-12'), (20, 'Fraud Fraud', '2016-12-31');
insert into employee (employee_id, employee_name)
values (1000, 'Cedrick French'), (1001, 'Jane Phillips'), (1002, 'Brian Green'), (1003, 'Shawn Brooks'), (1004, 'Clarence Thomas');
insert into cust_emp (emp_id, cust_id, start_date, end_date)
values (1000, 1, '2016-01-01', '2016-02-01'), (1000, 1, '2016-02-01', '2016-02-01'), (1000, 2,'2016-01-05', '2016-01-16'),(1000, 3,'2016-02-09', '2016-03-14'),(1000, 4,'2016-03-20', '2016-04-23'),
(1000, 5,'2016-01-01', '2016-01-16'),(1000, 6,'2016-01-01', '2016-01-16'),(1004, 7, '2016-01-14', '206-01-16'),
(1004, 8, '2016-01-13', '2016-01-16'),(1004, 9, '2016-01-05', '2016-01-16'), (1003, 12, '2016-04-21', '2016-11-30');
insert into cust_emp (emp_id, cust_id, start_date, deleted_yn)
values (1002, 11, '2016-04-10', TRUE),(1003, 10, '2016-01-16', FALSE), (1004, 12, '2016-04-20', TRUE), (1004, 12, '2016-04-19', FALSE), (1003, 13, '2016-06-06', TRUE), (1002, 14, '2016-06-10', TRUE),
(1004, 15, '2016-03-25', TRUE), (1004, 17, '2016-01-02', TRUE), (1004, 18, '2017-01-01', TRUE), (1004, 19, '2016-11-13', TRUE), (1004, 20, '2016-03-10', TRUE), (1004, 16, '2016-05-13', TRUE);
insert into cust_emp (emp_id, cust_id, start_date)
values (1002, 1, '2016-02-01'), (1004, 2, '2016-01-16'),(1003, 3, '2016-03-14'),(1002, 4, '2016-04-23'),(1004, 5, '2016-01-16'),(1002, 6, '2016-01-16'),(1004, 7, '2016-01-16'),
(1004, 8, '2016-01-16'),(1002, 9, '2016-01-16'), (1004, 10, '2016-01-16');
The following SQL works fine in MySQL but when I try it in Oracle, I get an 'invalid identifier' on 'dates':
select distinct(ce.start_date) as dates,
(select count(distinct(c.customer_id))
from customers c
inner join cust_emp ce on c.customer_id = ce.cust_id
where ce.start_date < dates
and (ce.end_date > dates or (ce.deleted_yn = false or ce.deleted_yn is null))
and (c.term_date > dates or c.term_date is null)
)
from cust_emp as ce;
It seems as though this is because the dates is too far in a subquery. I've tried a CTE as well, but that seems to have the same issue as it gave the same error. How can I re-write this so that I can assess how many customers were there for each date in Oracle?

Huh?
Isn't this what you want?
select ce.dates as dates, count(distinct c.customer_id)
from cust_emp ce join
customers c
on c.customer_id = ce.cust_id
where ce.start_date < ce.dates and
(ce.end_date > ce.dates or ce.deleted_yn = false or ce.deleted_yn is null) and
(c.term_date > ce.dates or c.term_date is null)
group by ce.dates
order by ce.dates;
I don't really understand the use of the subquery with select distinct. The logic you describe is more easily understood as a simple aggregation.
I'm not sure where dates comes from. It is not in your data model, but it is in your sample query.

Related

Group table results with information from another

I'm trying to perform a query that returns an aggregation of values from the same table with information from others through a foreign key, but I can't. In the example below, I wanted to return the total sales by state on 2020-01-01 and 2021-01-01, showing the name of the state.
Tables script:
CREATE TABLE IF NOT EXISTS estado (
id SERIAL PRIMARY KEY,
estado VARCHAR(100)
)
CREATE TABLE IF NOT EXISTS municipio (
id SERIAL PRIMARY KEY,
estado integer REFERENCES estado(id),
municipio VARCHAR(100)
)
CREATE TABLE IF NOT EXISTS vendas (
id SERIAL PRIMARY KEY,
municipio integer REFERENCES municipio(id),
valor numeric,
data_venda date
)
INSERT INTO estado VALUES (1, 'PR');
INSERT INTO estado VALUES (2, 'SC');
INSERT INTO estado VALUES (3, 'RS');
INSERT INTO municipio VALUES (1, 1, 'Pelotas');
INSERT INTO municipio VALUES (2, 1, 'Caxias do Sul');
INSERT INTO municipio VALUES (3, 1, 'Porto Alegre');
INSERT INTO municipio VALUES (4, 2, 'Florianopolis');
INSERT INTO municipio VALUES (5, 2, 'Chapeco');
INSERT INTO municipio VALUES (6, 2, 'Itajai');
INSERT INTO municipio VALUES (7, 3, 'Curitiba');
INSERT INTO municipio VALUES (8, 3, 'Maringa');
INSERT INTO municipio VALUES (9, 3, 'Foz do Iguaçu');
INSERT INTO vendas VALUES (1, 6, 5, '2020-01-01');
INSERT INTO vendas VALUES (2, 5, 10, '2021-01-01');
INSERT INTO vendas VALUES (3, 5, 5, '2020-01-01');
INSERT INTO vendas VALUES (4, 4, 2, '2020-01-01');
INSERT INTO vendas VALUES (5, 3, 10, '2021-01-01');
INSERT INTO vendas VALUES (6, 3, 12, '2020-01-01');
INSERT INTO vendas VALUES (7, 3, 20, '2020-01-01');
INSERT INTO vendas VALUES (8, 2, 10, '2020-01-01');
INSERT INTO vendas VALUES (9, 1, 11, '2021-01-01');
INSERT INTO vendas VALUES (10, 9, 4, '2020-01-01');
My attempt (absurd values and the RS ones do not appear):
SELECT
e.estado, SUM(v.valor) as sum2021, SUM(v2.valor) as sum2020
FROM vendas v
CROSS JOIN vendas v2
INNER JOIN municipio m ON v.municipio = m.id
INNER JOIN estado e ON m.estado = e.id
WHERE v.data_venda = '2021-01-01'
AND v2.data_venda = '2020-01-01'
GROUP BY 1;
Translating some terms:
município = city
estado = state
vendas = sales
valor = value
data_venda = date of sale
You're cross joining vendas with itself (as v1 and v2), meaning that each row from it will be matched with each other row (i.e., a Cartesian product), which creates the unexpected results you're seeing.
The good news is that you don't need this join. You can use an aggregate function (sum in this case) on a subset of the rows from the query using the filter clause:
SELECT
e.estado,
SUM(v.valor) FILTER (WHERE data_venda = '2021-01-01') AS sum2021,
SUM(v.valor) FILTER (WHERE data_venda = '2020-01-01') AS sum2020
FROM vendas v
INNER JOIN municipio m ON v.municipio = m.id
INNER JOIN estado e ON m.estado = e.id
GROUP BY
e.estado;
SQLFiddle demo

summing by rows sql

I attempted to do it using the analytical function, but it appears that I did so improperly...
How can I receive the output from the table I've been given?
CREATE TABLE rides (
ride_id INT,
driver_id INT,
ride_in_kms INT,
ride_fare FLOAT,
ride_date DATE
);
INSERT INTO rides VALUES (1, 1, 3, 4.45, "2016-05-16");
INSERT INTO rides VALUES (2, 1, 4, 8.46, "2016-05-16");
INSERT INTO rides VALUES (3, 2, 6, 11.9, "2016-05-16");
INSERT INTO rides VALUES (4, 3, 3, 6.76, "2016-05-16");
INSERT INTO rides VALUES (5, 2, 6, 13.55, "2016-05-16");
INSERT INTO rides VALUES (6, 4, 3, 4.91, "2016-05-20");
INSERT INTO rides VALUES (7, 1, 7, 16.77, "2016-05-20");
INSERT INTO rides VALUES (8, 3, 9, 16.18, "2016-05-20");
INSERT INTO rides VALUES (9, 2, 3, 6.07, "2016-05-20");
INSERT INTO rides VALUES (10, 4, 4, 6.25, "2016-05-20");
Output result
Thanks in advance
The general gist is to use an expression within the sum() to operate on the correct rows:
select
driver_id,
sum(case when ride_date = "2016-05-16" then ride_in_kms else 0 end) `KMS_MAY_16`,
sum(case when ride_date = "2016-05-20" then ride_in_kms else 0 end) `KMS_MAY_20`
from
group by driver_id;
The particular syntax available, and how to express the column label depends on what database you are using.

Finding top 10 products sold in a year

I have these tables below along with the definition. I want to find top 10 products sold in a year after finding counts and without using aggregation and in an optimized way. I want to know if aggregation is still needed or I can accomplish it without using aggregation. Below is the query. Can anyone suggest a better approach.
CREATE TABLE Customer (
id int not null,
first_name VARCHAR(30),
last_name VARCHAR(30),
Address VARCHAR(60),
State VARCHAR(30),
Phone text,
PRIMARY KEY(id)
);
CREATE TABLE Product (
ProductId int not null,
name VARCHAR(30),
unitprice int,
BrandID int,
Brandname varchar(30),
color VARCHAR(30),
PRIMARY KEY(ProductId)
);
Create Table Sales (
SalesId int not null,
Date date,
Customerid int,
Productid int,
Purchaseamount int,
PRIMARY KEY(SalesId),
FOREIGN KEY (Productid) REFERENCES Product(ProductId),
FOREIGN KEY (Customerid) REFERENCES Customer(id)
)
Sample Data:
insert into
Customer(id, first_name, last_name, address, state, phone)
values
(1111, 'andy', 'johnson', '123 Maryland Heights', 'MO', 3211451234),
(1112, 'john', 'smith', '237 Jackson Heights', 'TX', 3671456534),
(1113, 'sandy', 'fleming', '878 Jersey Heights', 'NJ', 2121456534),
(1114, 'tony', 'anderson', '789 Harrison Heights', 'CA', 6101456534)
insert into
Product(ProductId, name, unitprice, BrandId, Brandname)
values
(1, 'watch',200, 100, 'apple'),
(2, 'ipad', 429, 100, 'apple'),
(3, 'iphone', 799, 100, 'apple'),
(4, 'gear', 300, 110, 'samsung'),
(5, 'phone',1000, 110, 'samsung'),
(6, 'tab', 250, 110, 'samsung'),
(7, 'laptop', 1300, 120, 'hp'),
(8, 'mouse', 10, 120, 'hp'),
(9, 'monitor', 400, 130, 'dell'),
(10, 'keyboard', 40, 130, 'dell'),
(11, 'dvddrive', 100, 130, 'dell'),
(12, 'dvddrive', 90, 150, 'lg')
insert into
Sales(SalesId, Date, CustomerID, ProductID, Purchaseamount)
values (30, '01-10-2019', 1111, 1, 200),
(31, '02-10-2019', 1111, 3, 799),
(32, '03-10-2019', 1111, 2, 429),
(33, '04-10-2019', 1111, 4, 300),
(34, '05-10-2019', 1111, 5, 1000),
(35, '06-10-2019', 1112, 7, 1300),
(36, '07-10-2019', 1112, 9, 400),
(37, '08-10-2019', 1113, 5, 2000),
(38, '09-10-2019', 1113, 4, 300),
(39, '10-10-2019', 1113, 3, 799),
(40, '11-10-2019', 1113, 2, 858),
(41, '01-10-2020', 1111, 1, 400),
(42, '02-10-2020', 1111, 2, 429),
(43, '03-10-2020', 1112, 7, 1300),
(44, '04-10-2020', 1113, 7, 2600),
(45, '05-10-2020', 1114, 7, 1300),
(46, '06-10-2020', 1114, 7, 1300),
(47, '07-10-2020', 1114, 9, 800)
Tried this:
SELECT PCY.Name, PCY.Year, PCY.SEQNUM
FROM (SELECT P.Name AS Name, Extract('Year' from S.Date) AS YEAR, COUNT(P.Productid) AS CNT,
RANK() OVER (PARTITION BY Extract('Year' from S.Date) ORDER BY COUNT(P.Productid) DESC) AS RANK
FROM Sales S inner JOIN
Product P
ON S.Productid = P.Productid
) PCY
WHERE PCY.RANK <= 10;
I am seeing this error:
ERROR: column "p.name" must appear in the GROUP BY clause or be used in an aggregate function
LINE 2: FROM (SELECT P.Name AS Name, Extract('Year' from S.Date) AS ...
^
SQL state: 42803
Character: 52
I don't understand why you don't want to use an aggregate function when you have to aggregate over your data. This query works fine, without any issues on the GROUP BY:
WITH stats AS (
SELECT EXTRACT
( YEAR FROM DATE ) AS y,
P.productid,
P.NAME,
COUNT ( * ) numbers_sold,
RANK ( ) OVER ( PARTITION BY EXTRACT ( YEAR FROM DATE ) ORDER BY COUNT ( * ) DESC ) r
FROM
product
P JOIN sales S ON S.Productid = P.Productid
GROUP BY
1,2
)
SELECT y
, name
, numbers_sold
FROM stats
WHERE r <= 10;
This works because the productid is the primary key that has a functional dependency to the product name.
By the way, tested on version 12, but it should work on older and newer versions as well.

Can I improve this query for use in large tables?

How can I improve this query for use in large tables....?
I use a table ('DataValues') to store a collection of values ('Value') for collections ('Visit_id') ie it records certain values for each visit.
I use a table ('MatchItems') to store dynamic match sets 'MatchSet' of values ('Value'), sets can contain any number of values. The table also has a IsNeg field to indicate if the match should require a value to be not present in the visit collection.
This allows me to dynamically match visits that conform to certain criteria such as
Must contain values A, B and C and NOT D OR C and B AND NOT A.
ie (Value = A and Value = B and Value = C and Value /= D)
or (Value = C and Value = B and Value /= A)
I have a query that delivers a reasonable solution fiddle:
CREATE TABLE DataValues (
id NUMBER(5) CONSTRAINT DataValues_pk PRIMARY KEY,
Visit_id Number(5) ,
Value varchar(5)
);
INSERT INTO DataValues VALUES (1, 1, 'M');
INSERT INTO DataValues VALUES (2, 1, 'I');
INSERT INTO DataValues VALUES (3, 1, 'C');
INSERT INTO DataValues VALUES (4, 1, 'K');
INSERT INTO DataValues VALUES (5, 1, 'E');
INSERT INTO DataValues VALUES (6, 1, 'Y');
INSERT INTO DataValues VALUES (7, 2, 'M');
INSERT INTO DataValues VALUES (8, 2, 'O');
INSERT INTO DataValues VALUES (9, 2, 'U');
INSERT INTO DataValues VALUES (10, 2, 'S');
INSERT INTO DataValues VALUES (11, 2, 'E');
INSERT INTO DataValues VALUES (12, 3, 'C');
INSERT INTO DataValues VALUES (13, 3, 'A');
INSERT INTO DataValues VALUES (14, 3, 'T');
INSERT INTO DataValues VALUES (15, 4, 'S');
INSERT INTO DataValues VALUES (16, 4, 'A');
INSERT INTO DataValues VALUES (17, 4, 'T');
INSERT INTO DataValues VALUES (18, 5, 'M');
INSERT INTO DataValues VALUES (19, 5, 'A');
INSERT INTO DataValues VALUES (20, 5, 'T');
CREATE TABLE MatchItems (
id NUMBER(5) CONSTRAINT MatchItems_pk PRIMARY KEY,
MatchSet Number(5),
Value VARCHAR(5),
IsNeg NUMBER(1) NOT NULL CHECK (IsNeg in (0,1))
);
INSERT INTO MatchItems VALUES (1, 1, 'M', 0);
INSERT INTO MatchItems VALUES (2, 1, 'I', 0);
INSERT INTO MatchItems VALUES (3, 1, 'C', 0);
INSERT INTO MatchItems VALUES (4, 1, 'K', 0);
INSERT INTO MatchItems VALUES (5, 1, 'E', 0);
INSERT INTO MatchItems VALUES (6, 1, 'Y', 0);
INSERT INTO MatchItems VALUES (7, 2, 'C', 0);
INSERT INTO MatchItems VALUES (8, 2, 'A', 0);
INSERT INTO MatchItems VALUES (9, 3, 'A', 0);
INSERT INTO MatchItems VALUES (10, 3, 'T', 0);
INSERT INTO MatchItems VALUES (11, 4, 'S', 1);
INSERT INTO MatchItems VALUES (12, 4, 'A', 0);
INSERT INTO MatchItems VALUES (13, 4, 'K', 1);
INSERT INTO MatchItems VALUES (14, 5, 'A', 0);
INSERT INTO MatchItems VALUES (15, 5, 'T', 0);
SELECT
MatchItems.MatchSet,
DataValues.Visit_id,
GpMatchItems.Count TgtCount,
Count(MatchItems.Id),
sum(MatchItems.IsNeg)
FROM DataValues
LEFT JOIN MatchItems ON MatchItems.Value = DataValues.Value
--AND MatchItems.MatchSet = 4
LEFT JOIN (SELECT
MatchItems.MatchSet,
count(*) Count
FROM MatchItems
WHERE
MatchItems.IsNeg = 0
GROUP BY
MatchItems.MatchSet) GpMatchItems ON GpMatchItems.MatchSet = MatchItems.MatchSet
HAVING
Count(MatchItems.Id) = GpMatchItems.Count
AND sum(MatchItems.IsNeg) = 0
GROUP BY
MatchItems.MatchSet,
DataValues.Visit_id,
GpMatchItems.Count
How can I improve the performance of this query where the DataValues table contains 100m records, and MatchItems may include a collection of 50 sets each of 2 - 20 values?
You can try this version using Analytic functions and see if it performs any better. This query removes the subquery GpMatchItems that you are joining with.
SELECT DISTINCT matchset,
visit_id,
tgtcount,
match_visit_count,
isneg_sum
FROM (SELECT MatchItems.MatchSet,
DataValues.Visit_id,
COUNT (DISTINCT CASE MatchItems.IsNeg WHEN 0 THEN MatchItems.id ELSE NULL END)
OVER (PARTITION BY MatchItems.MatchSet)
AS tgtcount,
COUNT (*) OVER (PARTITION BY MatchItems.MatchSet, DataValues.Visit_id)
AS match_visit_count,
SUM (MatchItems.IsNeg) OVER (PARTITION BY MatchItems.MatchSet, DataValues.Visit_id)
AS isneg_sum
FROM DataValues LEFT JOIN MatchItems ON MatchItems.VALUE = DataValues.VALUE)
WHERE tgtcount = match_visit_count AND isneg_sum = 0;
I have adjusted EJ's suggestion to include a LEFT JOIN to collect the tgtCount to identify the total number of good matches required in each MatchSet:
SELECT DISTINCT matchset,
visit_id,
tgtcount,
match_visit_count,
isneg_sum
GpMatchItems.count tgtCount
FROM
COUNT (*) OVER (PARTITION BY MatchItems.MatchSet, DataValues.Visit_id)
AS match_visit_count,
SUM (MatchItems.IsNeg) OVER (PARTITION BY MatchItems.MatchSet, DataValues.Visit_id)
AS isneg_sum
FROM DataValues
LEFT JOIN MatchItems ON MatchItems.VALUE = DataValues.VALUE)
LEFT JOIN ( SELECT
MatchItems.MatchSet,
count(*) Count
FROM MatchItems
WHERE MatchItems.IsNeg = 0
GROUP BY
MatchItems.MatchSet) GpMatchItems
ON GpMatchItems.MatchSet = MatchItems.MatchSet
)
WHERE
tgtcount = match_visit_count
AND isneg_sum = 0;

Select duplicate persons with duplicate memberships

SQL Fiddle with schema and my intial attempt.
CREATE TABLE person
([firstname] varchar(10), [surname] varchar(10), [dob] date, [personid] int);
INSERT INTO person
([firstname], [surname], [dob] ,[personid])
VALUES
('Alice', 'AA', '1/1/1990', 1),
('Alice', 'AA', '1/1/1990', 2),
('Bob' , 'BB', '1/1/1990', 3),
('Carol', 'CC', '1/1/1990', 4),
('Alice', 'AA', '1/1/1990', 5),
('Kate' , 'KK', '1/1/1990', 6),
('Kate' , 'KK', '1/1/1990', 7)
;
CREATE TABLE person_membership
([personid] int, [personstatus] varchar(1), [memberid] int);
INSERT INTO person_membership
([personid], [personstatus], [memberid])
VALUES
(1, 'A', 10),
(2, 'A', 20),
(3, 'A', 30),
(3, 'A', 40),
(4, 'A', 50),
(4, 'A', 60),
(5, 'T', 70),
(6, 'A', 80),
(7, 'A', 90);
CREATE TABLE membership
([membershipid] int, [memstatus] varchar(1));
INSERT INTO membership
([membershipid], [memstatus])
VALUES
(10, 'A'),
(20, 'A'),
(30, 'A'),
(40, 'A'),
(50, 'T'),
(60, 'A'),
(70, 'A'),
(80, 'A'),
(90, 'T');
There are three tables (as per the fiddle above). Person table contains duplicates, same people entered more than once, for the purpose of this exercise we assume that a combination of the first name, surname and DoB is enough to uniquely identify a person.
I am trying to build a query which will show duplicates of people (first name+surname+Dob) with two or more active entries in the Person table (person_membership.person_status=A) AND two or more active memberships (membership.mestatus=A).
Using the example from SQL Fiddle, the result of the query should be just Alice (two active person IDs, two active membership IDs).
I think I'm making progress with the following effort but it looks rather cumbersome and I need to remove Katie from the final result - she doesn't have a duplicate membership.
SELECT q.firstname, q.surname, q.dob, p1.personid, m.membershipid
FROM
(SELECT
p.firstname,p.surname,p.dob, count(*) as cnt
FROM
person p
GROUP BY
p.firstname,p.surname,p.dob
HAVING COUNT(1) > 1) as q
INNER JOIN person p1 ON q.firstname=p1.firstname AND q.surname=p1.surname AND q.dob=p1.dob
INNER JOIN person_membership pm ON p1.personid=pm.personid
INNER JOIN membership m ON pm.memberid = m.membershipid
WHERE pm.personstatus = 'A' AND m.memstatus = 'A'
Since you are using SQL Server windows function will be handy for this scenario. The following will give you the expected output.
SELECT firstname,surname,dob,personid,memberid
from(
SELECT firstname,surname,dob,p.personid,memberid
,Rank() over(partition by p.firstname,p.surname,p.dob order by p.personid) rnasc
,Rank() over(partition by p.firstname,p.surname,p.dob order by p.personid desc) rndesc
FROM [StagingGRG].[dbo].[person] p
INNER JOIN person_membership pm ON p.personid=pm.personid
INNER JOIN membership m ON pm.memberid = m.membershipid
where personstatus='A' and memstatus='A')a
where a.rnasc+rndesc>2
You have to add Group by and Having clause to return duplicate items only-
SELECT
person.firstname,person.surname,person.dob
FROM
person, person_membership, membership
WHERE
person.personid=person_membership.personid AND person_membership.memberid = membership.membershipid
AND
person_membership.personstatus = 'A' AND membership.memstatus = 'A'
GROUP BY
person.firstname,person.surname,person.dob
HAVING COUNT(1) > 1