SQL WHERE Syntax
SELECT column_name(s)
FROM table_name WHERE column_name operator value |
WHERE Clause Example
Id
|
LastName
|
FirstName
|
Address
|
City
|
1
|
Navis
|
Anto
|
Madras
|
TVL
|
2
|
ji
|
Bala
|
Bombay
|
TVL
|
3
|
Christopher
|
Franklin
|
America
|
KK
|
Now we want to select only the persons living in the city "TVL" from the table above.
We use the following SELECT statement:
SELECT * FROM Persons
WHERE City='TVL' |
The result-set will look like this:
Id
|
LastName
|
FirstName
|
Address
|
City
|
1
|
Navis
|
Anto
|
Madras
|
TVL
|
2
|
Ji
|
Bala
|
Bombay
|
TVL
|
Quotes Around Text Fields
SQL uses single quotes around text values (most database systems
will also accept double quotes).Although, numeric values should not be enclosed in quotes.
For text values:
This is correct:
SELECT * FROM Persons WHERE FirstName='Bala' This is wrong: SELECT * FROM Persons WHERE FirstName=Bala |
For numeric values:
This is correct:
SELECT * FROM Persons WHERE Year=1965 This is wrong: SELECT * FROM Persons WHERE Year='1965' |
Operators Allowed in the WHERE Clause
With the WHERE clause, the following operators can be used:
Operator
|
Description
|
=
|
Equal
|
<>
|
Not equal
|
>
|
Greater than
|
<
|
Less than
|
>=
|
Greater than or equal
|
<=
|
Less than or equal
|
BETWEEN
|
Between an inclusive range
|
LIKE
|
Search for a pattern
|
IN
|
If you know the exact value you want to
return for at least one of the columns
|
Note: In some versions of SQL the <> operator may be written as !=
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