Описание операторов

OR

Пример оператора

There is a table "Persons":

For this we use this query:

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SELECT * FROM Persons
WHERE FirstName=
AND LastName=

Query Result:

For this we use this query:

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SELECT * FROM Persons
WHERE FirstName=
OR FirstName='

Query Result:

For this we use this query:

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SELECT * FROM Persons WHERE
LastName=
AND (FirstName= OR FirstName=)

Query Result: