The difference between a left (outer) join and a right (outer) join is: SQL?

Question

The difference between a left (outer) join and a right (outer) join is:

a)The table in the FROM clause in the left join becomes the table in the ON clause in the right join and vice versa.

b)A left join is a union thing, you should not be teaching political propaganda in 280!

c)A right join joins records in the table in the FROM clause that have no counterpart in the table in the ON clause.

d)A left join does not join records in the table in the FROM clause that have no counterpart in the table in the ON clause.

Answer 1

Even tho this is obviously yet another homework question of yours, I'll answer this one because it was so poorly phrased as to be cryptic.



SELECT FROM someTable1

LEFT OUTER JOIN someTable2 ON WHERE





SELECT FROM someTable1

RIGHT OUTER JOIN someTable2 ON WHERE



In the first case, you expect data from all rows of someTable1 that fit the WHERE criteria along with any data from someTable2 that fits the ON and WHERE criteria. In the second case, just the opposite. The only answer that fits (albeit phrased horribly) is D.

Answer 2

The "area" (i.e., left or impressive) of the table is in keeping with its place interior the sq. fact with appreciate to the "connect" clause. Taking the pattern fact from w3schools: go with persons.LastName, persons.FirstName, Orders.OrderNo FROM persons LEFT connect Orders ON persons.P_Id=Orders.P_Id ORDER by persons.LastName; persons is the "left" table, jointly as Orders is the "impressive" table. wish this helped. EDIT: to keep away from confusion, this is the significant phase of the sq. fact: persons LEFT connect Orders right here, it is clearer which table is left and which one is physically powerful.

Answer 3

makes no sense