select * from PRODUCTS where reference not null

select * from PRODUCTS

select distinct id from PRODUCTS

Select * Where Client From address = "Paris"

Select Distinct(*) Where Client From address = "Paris"

Select * From Client Where address = "Paris"

Where

From

Order By

Select

Select three columns of the table COURSES, the third column of which has the constant value " = PRICE". Sort the data according to the second column in ascending order.

Select two columns of the table COURSES, the second  of which has the constant value " = PRICE". Sort the data according to the second column in ascending order.

Select three columns of the table COURSES, the third of which has the constant value " = PRICE". Leave a blank row after every second row.

Select two columns of the table COURSES, the second of which is given the title " = PRICE". Sort the data according to the second column in ascending order.