left
UK[left] 美[lɛft]
adj.Left, left;leftist
n.Left , left; [military] left wing; left wing, radical
adv. to the left; on the left
v. to leave (past tense and past participle of leave)
plural ： lefts
join
UK[dʒɔɪn] US[dʒɔɪn]
vt.& vi.Join;participate;connect;connection
vt.Participate; combine; get on (train, plane, etc.); get on (road)
n.Connect; combine; join; joint point
Third person singular: joins now Participle: joining Past tense: joined Past participle: joined
mysql LEFT JOIN keyword syntax
Function:The LEFT JOIN keyword will return all rows from the left table (table_name1), even if there are no matching rows in the right table (table_name2).
Syntax:SELECT column_name(s) FROM table_name1 LEFT JOIN table_name2 ON table_name1.column_name=table_name2.column_name
Comments:In some databases , LEFT JOIN is called LEFT OUTER JOIN.
mysql LEFT JOIN keyword example
//列出所有的人，以及他们的定购 - 如果有的话 SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo FROM Persons LEFT JOIN Orders ON Persons.Id_P=Orders.Id_P ORDER BY Persons.LastName;