Sql-server – Removing duplicates values with join

duplicationsql server

I have a query that looks like this:

SELECT
B.Company,
COUNT(*) AS QTY
FROM Table1 A
INNER JOIN Table2 B
ON A.CompanySk = B.EDWCompanySK
WHERE A.StartedDate >= '20171128'
GROUP BY B.Company
ORDER BY QTY DESC

However, there is a field name "Ticket" in table1 that has duplicate values, that I need to exclude. How can I return the count with excluding duplicate "ticket" values.

Best Answer

Use the next query

SELECT
B.Company,
COUNT(DISTINCT A.Ticket) AS QTY
FROM Table1 A
INNER JOIN Table2 B
ON A.CompanySk = B.EDWCompanySK
WHERE A.StartedDate >= '20171128'
GROUP BY B.Company
ORDER BY QTY DESC

Related Solutions

Mysql – remove duplicate rows in thesql table that does not contain primary key

In the spirit of @yercube's answer, I have an answer that has an added twist.

CREATE TABLE stage
(
    id int not null auto_increment,
    name varchar(20),
    primary key (id)
);
CREATE TABLE stage2 LIKE stage;
INSERT INTO stage (name) SELECT name FROM item;
INSERT INTO stage2 (id) SELECT min_id FROM
(SELECT MIN(id) min_id,name FROM stage GROUP BY name) A;
UPDATE stage2 A INNER JOIN stage B USING (id) SET A.name=B.name;
TRUNCATE TABLE item;
INSERT INTO item (name) SELECT name FROM stage2;
DROP TABLE stage;
DROP TABLE stage2;

This will load stage2 with the first occurrence of each name from item, zap the item table, and load the unique occurrences back.

If you look back in @yercube's answer and compare it to my answer, his is much more simplistic because

@yercube uses one temp table, while I use two
I had to create a column for iteration control, @yercube did not need to
@yercube has fewer steps
both answers achieve the same thing

I do not expect my answer to be accepted. The sole purpose of my answer was demonstrate that other answers lose the concise clarity needed to solve your problem. Again, hats off to @yercube.

Sql-server – Single sql query to select a record from parent table only if all it’s records in child table has values

This is called an "anti-join" (or anti-semijoin). One way to write it in SQL is to use the NOT EXISTS construction:

SELECT t1.*
FROM Table1 AS t1
WHERE NOT EXISTS
      ( SELECT *
        FROM Table2 AS t2
        WHERE t2.FKcolumn = t1.PKcolumn
          AND t2.columnX IS NULL
      )

If - as your comment - you want a parent row (at Table1) not related to any child row (at Table2), to NOT be shown, add this (or join Table2 if you also want columns from the second table shown):

  AND EXISTS
      ( SELECT *
        FROM Table2 AS t2
        WHERE t2.FKcolumn = t1.PKcolumn
      )

Best Answer

Related Solutions

Mysql – remove duplicate rows in thesql table that does not contain primary key

Sql-server – Single sql query to select a record from parent table only if all it’s records in child table has values

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