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33-year-old because of abdominal pain constipation to the hospital, the result was diagnosed with sigmoid colon cancer, through inquiry learned that the patient likes to eat barbecue, usually never eat vegetables and fruits, the patient's father is also because

33 years old because of abdominal pain constipation to the hospital, the result was diagnosed with sigmoid colon cancer, through inquiry learned that the patient likes to eat barbecue, usually never eat vegetables and fruits, the patient's father also died of bowel cancer, the wife once suggested that the husband go to the hospital early to check, but the patient did not listen. As a doctor, we should remind everyone that the occurrence of colorectal cancer is related to heredity and eating habits, and those who have high risk factors must be checked in the hospital regularly.

Dr. Ding's gastrointestinal science book

33-year-old because of abdominal pain constipation to the hospital, the result was diagnosed with sigmoid colon cancer, through inquiry learned that the patient likes to eat barbecue, usually never eat vegetables and fruits, the patient's father is also because
33-year-old because of abdominal pain constipation to the hospital, the result was diagnosed with sigmoid colon cancer, through inquiry learned that the patient likes to eat barbecue, usually never eat vegetables and fruits, the patient's father is also because
33-year-old because of abdominal pain constipation to the hospital, the result was diagnosed with sigmoid colon cancer, through inquiry learned that the patient likes to eat barbecue, usually never eat vegetables and fruits, the patient's father is also because
33-year-old because of abdominal pain constipation to the hospital, the result was diagnosed with sigmoid colon cancer, through inquiry learned that the patient likes to eat barbecue, usually never eat vegetables and fruits, the patient's father is also because
33-year-old because of abdominal pain constipation to the hospital, the result was diagnosed with sigmoid colon cancer, through inquiry learned that the patient likes to eat barbecue, usually never eat vegetables and fruits, the patient's father is also because

資料庫的内連接配接、外連接配接(左外連接配接、右外連接配接、全外連接配接)以及交叉連接配接(轉)

轉自: 資料庫的内連接配接、外連接配接(左外連接配接、右外連接配接、全外連接配接)以及交叉連接配接

SQL資料庫的連接配接:内連接配接、和外連接配接(左外連接配接、右外連接配接、和全連接配接)

本次實驗在MySQL資料庫中進行,資料庫初始表如下:

資料庫的内連接配接、外連接配接(左外連接配接、右外連接配接、全外連接配接)以及交叉連接配接(轉)

一、内連接配接:結果僅包含符合連接配接條件的兩表中的行。如下:

資料庫的内連接配接、外連接配接(左外連接配接、右外連接配接、全外連接配接)以及交叉連接配接(轉)
資料庫的内連接配接、外連接配接(左外連接配接、右外連接配接、全外連接配接)以及交叉連接配接(轉)

二、外連接配接:結果包含符合條件的行,同時包含不符合條件的行(分為左外連接配接、右外連接配接和全外連接配接)

1、左外連接配接:左表全部行+右表比對的行,如果左表中某行在右表中沒有比對的行,則顯示NULL。如下:

資料庫的内連接配接、外連接配接(左外連接配接、右外連接配接、全外連接配接)以及交叉連接配接(轉)

2、右外連接配接:和左外連接配接相反。如下:

資料庫的内連接配接、外連接配接(左外連接配接、右外連接配接、全外連接配接)以及交叉連接配接(轉)

3、全外連接配接:不管比對不比對,全部顯示出來,左表在右邊沒有的顯示NULL,右表在左邊沒有的顯示NULL

(MySQL資料庫不支援全外連接配接,是以轉換了一種文法,原本寫法:

select * from student full join score on student.sno=score.sno;

資料庫的内連接配接、外連接配接(左外連接配接、右外連接配接、全外連接配接)以及交叉連接配接(轉)

三、交叉連接配接:傳回左表中所有行與右表中所有行的組合,也稱笛卡爾積

資料庫的内連接配接、外連接配接(左外連接配接、右外連接配接、全外連接配接)以及交叉連接配接(轉)