Computations in SQL Queries

• Functions SUM, AVG, MIN, MAX, COUNT are supported

• Select count(SKU)
  From SKU_DATA;
      

• Select sum(ExtendedPrice) 
  From ORDER_ITEM 
  Where OrderNumber=1000;
      

• The as option allows us to name the new column

• Select sum(ExtendedPrice) as TotalPrice 
  From ORDER_ITEM 
  Where OrderNumber=1000;
      

• You can do several of these at once:

• Select sum(ExtendedPrice) as ExtendedPrice,
         count(OrderNumber), 
         avg(Quantity), 
         sum(Quantity) 
  From ORDER_ITEM 
  Where OrderNumber=1000;
      

• Count can use a *, and disticnt may be necessairy

• Select count(Department) 
  From SKU_DATA;
  
  Select count(Distinct Department) 
  From SKU_DATA;
      

• String operations seem to be less standard.
• mysql has a huge list

• Select concat_ws(" in ", Buyer, Department) 
  From SKU_DATA;
      

• Select  Buyer, locate("D",Buyer) 
  From SKU_DATA;