Web programmer services required

We need a web programmer. You need to work with SQL.
The database contains 4 tables:
Item (mkr, mdl, tp)
Comp (cd, mdl, spd, rm, hd, cd, prc)
Note(cd, model, spd, rm, hd, prc, scrn)
Prn(cd, mdl, clr, tp, prc)
The Item table represents the manufacturer (mkr), model number (mdl) and type ('PC' for PC, 'Laptop' for PC notebook or 'Printer' for printer). The model numbers in the Item table are supposed to be unique to all manufacturers and product types. In the Comp table for each PC, uniquely defined by a unique code - cd, the model is indicated - mdl (external key to the Item table), speed - spd (processor in megahertz), memory - rm (in megabytes), disk size - hd (in gigabytes), speed of the reader - cd (for example, '4x') and price - prc. The Note table is similar to the Comp table except that instead of the speed of the CD, it contains the screen size of -scrn (in inches). The Prn table for each printer model indicates whether it is colored - clr ('y' if colored), printer type - tp (laser - 'Laser', inkjet - 'Jet' or matrix - 'Matrix') and price - prc.

It is necessary:
1. Indicate the model, speed and disk size of all PCs costing more than $400. Delete: mdl, spd and hd
2. Find the printers that have the highest price. Delete: mdl, prc
3. Indicate the average speed of the PC that the manufacturer A has released.
4. Find the average size of each of the manufacturers that produce printers. Output: mkr, medium HD size.
5.Find printer manufacturers that produce PCs with the smallest rm volume and the fastest processor of any PC with the smallest rm volume.