本篇為初學者自學第四篇，由於是自學筆記，撰寫角度以筆者本身需求為優先考量
菜鳥成就感 : 自己寫syntax找出解決方式，大概是最大的成就，即便這只是個小小的功能。
今天的任務是要找出兩張表(languages 和 countries)不同的地方且把不同之處顯示出來。
可以看出來這個language Table 中有955 筆資料 但是仔細觀察後，發現每個國家有多種語言，像是表中code欄位，找到AFG後發現總共有四個AFG的資料，其中name欄位有顯示出不同名稱，我們不難猜出，這就是語言的名字。所以光是阿富汗(AFG)這個光家就有四個語言了。但我想知道在這張表中包含的所有國家，我可以怎麼把國家總數列出來呢?
這時候你需要 DISTINCT 這個commander
SELECT DISTINCT code FROM languages; 查到這張表總共有212個國家!
本篇為初學者自學第二篇，由於是自學筆記，撰寫角度以筆者本身需求為優先考量。
BETWEEN
IS NULL
IS NOT NULL
DISTINCT
LIKE
Get the names of people whose names have ‘r’ as the second letter. The pattern you need is '_r%'.
SELECT name
FROM people
WHERE name LIKE ‘_r%’;
NOT LIKE
Get the names of people whose names don’t start with A. The pattern you need is 'A%'.
SELECT name
FROM people
WHERE name NOT LIKE ‘A%’;
本篇為初學者自學第一篇，由於是自學筆記，撰寫角度以筆者本身需求為優先考量。
基本起手式。 SELECT column FROM table’s name ;
SELECT
FROM
WHERE
OR
AND
COUNT
COUNT(DISTINCT)
As soon as 和 As long as 超像 只差一個字但意識卻完全不同
As soon as = immediately after(time)
As long as = if (condition), using at present tense.
So….As long as is based on condition(if)/for the duration
As long as you give a ride, I will go to the party tonight. I will go to the party tonight as long as you give a ride.
As long as I live, I will remember you. (The time duration)
As long as you are quiet, you can come.(Condition)
As long as I am here, I will help. (The time duration)
As long as you buy me lunch, I will help(Condition).
This is the way how I jow down my note.
