SQL Joins

--INNER JOIN: Returns all rows when there is at least one match in BOTH tables

--LEFT JOIN: Return all rows from the left table, and the matched rows from the right table

--RIGHT JOIN: Return all rows from the right table, and the matched rows from the left table

--FULL JOIN: Return all rows when there is a match in ONE of the tables

SELECT

       COUNT (*)

FROM

       [DataBase].dbo.TableA A

       INNER JOIN [DataBase].dbo.TableB B ON A.ColumnA = B.ColumnB

SELECT

       COUNT (*)

FROM

       [DataBase].dbo.TableA A

       LEFT JOIN [DataBase].dbo.TableB B ON A.ColumnA = B.ColumnB

SELECT

       COUNT (*)

FROM

       [DataBase].dbo.TableA A

       RIGHT JOIN [DataBase].dbo.TableB B ON A.ColumnA = B.ColumnB

SELECT

       COUNT (*)

FROM

       [DataBase].dbo.TableA A

       FULL JOIN [DataBase].dbo.TableB B ON A.ColumnA = B.ColumnB

SELECT

       COUNT (*)

FROM

       [DataBase].dbo.TableA A

       LEFT JOIN [DataBase].dbo.TableB B ON A.ColumnA = B.ColumnB

WHERE

              A.ColumnA IS NULL

SELECT

       COUNT (*)

FROM

       [DataBase].dbo.TableA A

       RIGHT JOIN [DataBase].dbo.TableB B ON A.ColumnA = B.ColumnB

WHERE

              A.ColumnA IS NULL

SELECT

       COUNT (*)

FROM

       [DataBase].dbo.TableA A

       LEFT JOIN [DataBase].dbo.TableB B ON A.ColumnA = B.ColumnB

WHERE

              B.ColumnB IS NULL

SELECT

       COUNT (*)

FROM

       [DataBase].dbo.TableA A

       RIGHT JOIN [DataBase].dbo.TableB B ON A.ColumnA = B.ColumnB

WHERE

              B.ColumnB IS NULL

SELECT

       COUNT (*)

FROM

       [DataBase].dbo.TableA A

       FULL OUTER JOIN [DataBase].dbo.TableB B ON A.ColumnA = B.ColumnB

SELECT

       COUNT (*)

FROM

       [DataBase].dbo.TableA A

       FULL OUTER JOIN [DataBase].dbo.TableB B ON A.ColumnA = B.ColumnB

WHERE

               A.ColumnA IS NULL

OR

              B.ColumnB IS NULL