django中使用原生sql語句的方法步驟

# row方法:（摻雜著原生sql和orm來執(zhí)行的操作）
res = CookBook.objects.raw('select id as nid from epos_cookbook where id>%s', params=[1, ])
print(res.columns) # ['nid']
print(type(res)) # class 'django.db.models.query.RawQuerySet'>

# 在select里面查詢到的數(shù)據(jù)orm里面的要一一對(duì)應(yīng)
res = CookBook.objects.raw("select * from epos_cookbook")
print(res)
for i in res:
  print(i.create_date)
  print(i)
  
res = CookBook.objects.raw('select * from epos_cookbook where id>%s', params=[1, ])
# 后面可以加參數(shù)進(jìn)來
print(res)
for i in res:
  # print(i.create_date)
  print(i)

## select提供簡單數(shù)據(jù)
# SELECT age, (age > 18) as is_adult FROM myapp_person;
Person.objects.all().extra(select={'is_adult': "age > 18"}) # 加在select后面

## where提供查詢條件
# SELECT * FROM myapp_person WHERE first||last ILIKE 'jeffrey%';
Person.objects.all().extra(where=["first||last ILIKE 'jeffrey%'"]) # 加一個(gè)where條件

## table連接其它表
# SELECT * FROM myapp_book, myapp_person WHERE last = author_last
Book.objects.all().extra(table=['myapp_person'], where=['last = author_last']) # 加from后面

## params添參數(shù)
# !! 錯(cuò)誤的方式 !!
first_name = 'Joe' # 如果first_name中有SQL特定字符就會(huì)出現(xiàn)漏洞
Person.objects.all().extra(where=["first = '%s'" % first_name])
# 正確方式
Person.objects.all().extra(where=["first = '%s'"], params=[first_name])

from django.db import connection

 cursor=connection.cursor()
 # 如果需要配置數(shù)據(jù)庫
 # cursor=connection['default'].cursor() 
 
 cursor.execute('select * from app01_book')

 ret=cursor.fetchall()

 print(ret)
 #((2, '小時(shí)光', Decimal('10.00'), 2), (3, '未來可期', Decimal('33.00'), 1), (4, '打破思維里的墻', Decimal('11.00'), 2), (5, '時(shí)光不散', Decimal('11.00'), 3))