Malumotlar bazasi Mavzu: Ma’lumotlar bazasini loyihalash. Mohiyat – aloqa diogrammasini qurish

RTRIM -funksiyasi satr oxiridagi bo'sh joyni olib tashlash orqali asl nusxadan olingan satrni qaytaradi.
LEFT -funktsiyasi asl satrning boshlang'ich satrini qaytaradi

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  RIGHT- funktsiyasi belgilangan sondan tashkil topgan pastki qatorni qaytaradi.
  
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  select upper(nomi) from pechene;
  

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  select replace(sifat,'alo','yaxshi') from pechene;
  

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  JOINlar bilan ishlash.
  
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  SELECT
  
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  column_names [,... n]
  
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  FROM
  
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  Table_1 INNER JOIN Table_2
  
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  ON condition
  
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  SELECT
  
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  column_names [,... n]
  
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  FROM
  
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  Table_1 LEFT JOIN Table_2
  
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  ON condition
  

# left va inner joinlar ishlash sintaksisi

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  select * from pechene left join shokolad on shokolad.miqdori=pechene.miqdori;
  

select * from sotilgan_p right join pechene on sotilgan_p.sanasi=pechene.sanasi;

Foydalanilgan adabiyotlar:

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  https://www.sqlshack.com/overview-of-sql-lower-and-sql-upper-functions/
  
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  https://www.databasestar.com/sql-upper-lower/
  
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  https://www.oreilly.com/library/view/sql-in-a/9780596155322/re94.html
  
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  https://stackoverflow.com/questions/36477856/sql-select-name-no-matter-upper-or-lower-case-letters
  
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  https://www.databasejournal.com/ms-sql/dealing-with-upper-and-lower-case-data/
  
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  https://techcommunity.microsoft.com/t5/azure-database-support-blog/sql-server-performance-upper-and-lower-functions-and-database/ba-p/3553406
  
• 
  https://www.educba.com/sql-ignore-case/
  

Xulosa
Bu mustaqil ishim orqali men Relatsion malumotlar bazasi haqida tushuncha oldim va NOT, OR, AND mantiqiy standart so’zlardan foydalanishni bilib oldim. SQL da Group by va Order by parametrlari orqali guruhlash va saralash mumkin ekan. Va SQLda bir qancha standart funksiyalarni foydalanishni organdim.