[Introduction]
DMsql refers to a database of dreams, here are just some plain sql. Actual operating results and data to explore the principle. We dream up a database table that comes with mysql table GRADE and free to create as a test.
1, the query all data
up to the dream database
select * from "SYSDBA" "GRADE ".;
mysql database
SELECT * FROM ceshi;
2, replacing the header
[plus without the effect is the same as]
DaMeng database
SELECT "the CLASSID" Frozen, "STU_COUNT" Red, ", TEACHER_NAME" as Red, "COURSE,"
from "the SYSDBA" "the GRADE.";
MySQL database
the SELECT the Test AS Frozen, NAME AS WCL, the FROM NAME WCL ceshi; 
3, in combination with the new column of mysql can only dream of digital mosaic, columns, or other characters can not be joined
up to the dream database
select (123232 + 213213) as frozen from "SYSDBA . "" GRADE "; 
MySQL database
the SELECT (1232 + 13121) AS Frozen the fROM ceshi; 
4, range queries
up to the dream database
the SELECT" CLASSID "," STU_COUNT "," TEACHER_NAME "," COURSE "
from" SYSDBA GRADE "". " the WHERE "STU_COUNT" the BETWEEN 20 and 38; 
MySQL database
the sELECT the FROM ceshi the WHERE Age the BETWEEN 30 and 80; 
5, according to the first letter of the investigation
[ps] up to the dream database according to ASCII (str) to sort, mysql when creating a general selection choice utf -8 as coded
DaMeng database
SELECT from "the SYSDBA" "the GRADE" by Order ", TEACHER_NAME.";
MySQL database
SELECT * FROM ceshi ORDER BY Name;
[Ps] mysql collation so what is it, explore what
the SELECT SUBSTRING (name, 1, 1), ASCII (SUBSTRING (name, 1, 1)) the FROM ceshi the ORDER BY SUBSTRING (name, 1, 1); 
6.1, (str) try to follow gbk ASCII?
SELECT SUBSTRING (name, 1,1), ASCII (CONVERT (SUBSTRING (name, 1,1) USING gbk)) FROM ceshi ORDER BY CONVERT (SUBSTRING (name, 1,1) USING gbk);
7, a replacement for the null character
up to the dream database
up to the dream of grammar with mysql there is no null data, it skipped.
mysql database
the SELECT the COALESCE (the Name, "Frozen") from ceshi; 
. 8, [advanced] condition returns case when
DaMeng database
SELECT , (case when "STU_COUNT" <40 the then 'fuel' else 'OK' end) as frozen from . "SYSDBA" "GRADE"; 
MySQL database
[ps] I think less than 100 are all human beings are immortal greater than 100.
The SELECT , (Age the WHEN the CASE <100 THEN "mortal" ELSE 'immortal' END) as frozen from ceshi;
9, aggregate functions
a, the AVG ()
the AVG () function calculates the average of a set of values. It ignores the calculation process is a NULL value.
DaMeng database
SELECT AVG ( "STU_COUNT") from "the SYSDBA" "the GRADE";.
MySQL database
SELECT AVG (Age) FROM ceshi;
Two, COUNT () function
DaMeng database mysql consistent
SELECT COUNT (*) FROM ceshi;
three, SUM () function
DaMeng database mysql consistent
SELECT SUM (Age) FROM ceshi;
four, MAX () function
select max ( " STU_COUNT ") from" SYSDBA GRADE " ." ";
five, mIN () function
SELECT min (" STU_COUNT ") from" the SYSDBA the GRADE "." ";
10, round functions
mysql database
delimiter $$$
create procedure zqtest() -- 创建函数
begin
declare i int default 0;
set i=0;
start transaction;
while i<12 do
INSERT into ceshi(uuid) VALUES (i);
set i=i+1;
end while;
commit;
end
$$$
delimiter;
call zqtest();
Create a complete implementation process, to run in the function.
got the answer: