What is the function of where phrase in sql command?

The function of the where phrase in the sql command is to specify the selection criteria and filter records; if you need to conditionally select data from the table, you can add the WHERE clause to the SELECT statement.

The WHERE clause is used to filter records. The WHERE clause is used to extract records that meet specified conditions.

To conditionally select data from a table, add a WHERE clause to the SELECT statement.

SQL WHERE syntax

SELECT column_name,column_name
FROM table_name
WHERE column_name operator value;

The following operators can be used in the WHERE clause:

##Note: In some versions of SQL, the operator can be written as !=.

Operator	Description
=	equals
	is not equal to
>	is greater than
	is less than
>=	greater than or equal to
	less than or equal to
BETWEEN	Search for a certain pattern within a certain range
LIKE

Use WHERE clause

If you only want to select people living in the city "Beijing", we need to add a WHERE clause to the SELECT statement:

SELECT * FROM Persons WHERE City='Beijing'

"Persons" table

Result:

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