In digital computer programming, a bitwise operation operates on one or more bit patterns or binary numerals at the level of their individual bits. It is a fast, simple action directly supported by the processor, and is used to manipulate values for comparisons and calculations. On simple low-cost processors, typically, bitwise operations are substantially faster than division, several times faster than multiplication, and sometimes significantly faster than addition. While modern processors usually perform addition and multiplication just as fast as bitwise operations due to their longer instruction pipelines and other architectural design choices, bitwise operations do commonly use less power because of the reduced use of resources.
CREATETABLE price
(
id INTPRIMARY KEY,
ap INTDEFAULTNULL,
bp INTDEFAULTNULL,
cp INTDEFAULTNULL,
p INTDEFAULTNULL
);
INSERTINTO price VALUES
(1,NULL,100,93,6),
(2,188,170,203,7),
(3,NULL,14,NULL,2);
INSERTINTO price VALUES
(4,NULL,NULL,NULL,NULL),
(5,44,55,66,7),
(6,NULL,NULL,430,4);
SELECT
id '产品编号',
CASEWHEN p&ap>0THEN ap
WHEN p&bp>0THEN bp
WHEN p&cp>0THEN cp
ELSE'该产品无有效报价'END'有效报价',
CASEWHEN p&ap>0THEN'ap'WHEN p&bp>0THEN'bp'WHEN p&cp>0THEN'cp'ELSE'无'END'报价主管'FROM price;