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SQL Interview Questions and Answers for Business Analyst

To help recruiters evaluate the SQL proficiency of potential Business Analysts, we have compiled a list of ten key SQL business analyst interview questions These questions cover various aspects of SQL, allowing recruiters to gauge a candidate's expertise and problem-solving skills. <br><br>To read the full article, visit https://www.hirequotient.com/blog/sql-interview-questions-for-business-analyst

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SQL Interview Questions and Answers for Business Analyst

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  1. S Q LI n t e rv i e wQ u e s t i o n sa n dA n s w e r s f o rB u s i n e s sA n a l y s t b yAmitThokal

  2. Q u e s t i o n 1 Q u e s t i o n A n s w e r W h a ti sS Q L , a n dw h a ta r ei t s S Q Ls t a n d sf o rS t r u c t u r e dQ u e ryL a n g u ag e. Iti sa p r o g r a m m i n gl a n g u ag eu s e dt om a n a g ea n d p r i m a ryc o m p o n e n t s ? m a n i p u l a t er e l a t i o n a ld a t ab a s e s. T h ep r i m a ry c o m p o n e n t so fS Q Li n c l u d eD a t aD e f i n i t i o n La n g u a g e (D D L) , D a t aMa n i p u l a t i o nL a n g u a g e (D M L) , D a t aC o n t r o lL a n g u ag e (D C L) , a n d T r a n s a c t i o nC o n t r o lLa n g u a g e (T C L) .

  3. Q u e s t i o n 2 Q u e s t i o n A n s w e r E x p l a i nth ed i f f e r e n c eb e t w e e n I N N E RJ O I Na n dL E F TJ O I N . IN N ERJ O I Nr e t u r n so n l yth em a t c h i n gr o wsf r o m b o tht a b l e s, b as e do nth es p e c i f i e dc o n d i t i o n. LE F TJ O IN, o nth eo th e rh a n d, r e t u r n sa l lth e r o wsf r o mth el e f tt a b l ea n dth em a t c h i n gr o ws f r o mth er i g h tt ab l e. Ifn om a t c hi sf o u n di nth e r i g h tt a b l e, N U L Lv a l u e sa r er e t u r n e d.

  4. Q u e s t i o n 3 Q u e s t i o n A n s w e r H o wc a ny o ue l i m i n a t ed u p l i c a t e T oe l i m i n a t ed u p l i c a t er o wsi naS Q Lq u e ryr e s u l t, th ec a n d i d a t ec a nu s etheD IS T IN C Tk e y w o r di n r o w si naS Q Lq u e ryr e s u l t ? th eS E L E C Ts t a t e m e n t. I te n s u r e sth a to n l y u n i q u ev a l u e sa r ed i s p l a y e di nth er e s u l ts e t.

  5. Q u e s t i o n 4 Q u e s t i o n A n s w e r W h a ti sth ep u r p o s eo fth e T h eG R O U PB Yc l a u s ei su s e dt og r o u pr o wsth a t ha v ethes a m ev a l u e si nas p e c i f i e dc o l u m n. Iti s G R O U PB Yc l a u s ei nS Q L ? t y p i c a l l yc o m b i n e dw i tha g g r e g a t ef u n c t i o n sl i k e S U M, A V G, C O U N T , e t c. , t op e rf o r mc a l c u l a t i o n s o nth eg r o u p e dd at a.

  6. Q u e s t i o n 5 Q u e s t i o n A n s w e r H o wd oy o uh a n d l eN U L Lv a l u e s i nS Q L ? N U LLv a l u e sc a nb eh a n d l e di nS Q Lu s i n g f u n c t i o n sl i k eI SN U L Lan dI SN O TN U L L. T h e s e f u n c t i o n sh e l pi d e n t i f ya n df i l t e rr o wswi thN U L L v a l u e s. A d d i t i o n a l l y , C O A L E S C Ef u n c t i o nc a nb e u s e dt or e p l a c eN U L Lv al u e sw i thas p e c i f i c al t e r n a t i v ev a l u e.

  7. Q u e s t i o n 6 Q u e s t i o n A n s w e r W h a ti sas u b q u e ryi nS Q L ? As u b q u e ry , a l s ok n o wna san e s t e dq u e ry , i sa q u e ryn e s t e di n s i d ea n o th e rq u e ry . Iti su s e dt o r e t r i e v ed a t ab a s e do nther e s u l t so fth ei n n e r q u e ry . T her e s u l to fth es u b q u e ryi sth e nu s e di n th eo u t e rq u e ry .

  8. Q u e s t i o n 7 Q u e s t i o n A n s w e r E x p l a i nth ec o n c e p to fi n d e x i n g i nd a t a b a s e s . In d e x i n gi nd a t a b a s e si n v o l v e sc r e a t i n gd at a s t r u c t u r e sth a ti m p r o v eth es p e e do fd a t a r e t r i e v a lo p e r a t i o n s. Itw o r k ss i m i l a rt oa ni n d e xi n ab o o k, a l l o wi n gth ed a t a b a s ee n g i n et ol o c at e s p e c i f i cd a t aq u i c k l y . I n d e x e sa r ec r e a t e do n c o l u m n st oe n h a n c es e a r c ho p e r a t i o n sb y o r g a n i z i n gth ed a t ai nas p e c i f i co r d e r , r e d u c i n g th en e e df o rf u l lt a b l es c a n s.

  9. Q u e s t i o n 8 Q u e s t i o n A n s w e r W h a ti sth ed i f f e r e n c eb e t w e e n U N I O Na n dU N I O NA L Li nS Q L ? U N IO Ni su s e dt oc o m b i n eth er e s u l ts e t so ft w o o rm o r eS E L E C Ts t a t e m e n t si n t oas i n g l er e s u l t s e t, e x c l u d i n ga n yd u p l i c a t er o ws. U N IO NA L L, o n th eo th e rh a n d, c o m b i n e sth er e s u l ts e t so f m u l t i p l eS EL E C Ts t a t e m e n t s, i n c l u d i n gd u p l i c a t e r o ws.

  10. Q u e s t i o n 9 Q u e s t i o n A n s w e r H o wd oy o uo p t i m i z eas l o w - p e rf o r m i n gS Q Lq u e ry ? T oo p t i m i z eas l o w-p e rf o r m i n gS Q Lq u e ry , s e v e r a la p p r o a c h e sc a nb et a k e n. S o m ec o m m o n s t r a t e g i e si n c l u d e: - A n a l y z i n gth eq u e rye x e c u t i o np l a na n d i d e n t i f y i n ga n ym i s s i n gi n d e x e s. - R e f a c t o r i n gth eq u e ryt ou s em o r ee f f i c i e n t JO I N so rs u b q u e r i e s. - L i m i t i n gth ed a t ar e t r i e v e db yad d i n g ap p r o p r i a t ef i l t e r so rc o n d i t i o n s. - C a c h i n gf r e q u e n tl ya c c e s s e dd a t ao ru t i l i z i n g d a t a b a s ec a c h i n gm e c h a n i s m s. - P a rt i t i o n i n go ri n d e x i n gt a b l e sb a s e do na c c e s s p a t t e r n s.

  11. Q u e s t i o n 1 0 Q u e s t i o n A n s w e r E x p l a i nA C I Dp r o p e rt i e si nth e A C IDs t a n d sf o rA t o m i c i t y , C o n s i s t e n c y , I s o l a t i o n, an dD u r a b i l i t y , wh i c ha r eth ek e yp r o p e rt i e so fa c o n t e x to fd a t a b a s e r e l i a b l ed a t ab a s et r a n s a c t i o n: t r a n s a c t i o n s . - A t o m i c i t ye n s u r e sth a tat r an s a c t i o ni st r e a t e d asas i n g l e, i n d i v i s i b l eu n i to fw o r k. I te i th e r s u c c e e d sc o m p l e t e l yo rf a i l s, l e a v i n gn o i n t e r m e d i a t es t a t e. - C o n s i s t e n c ye n s u r e sth a tat r an s a c t i o nb r i n g s th ed a t a b a s ef r o mo n ec o n s i s t e n ts t at et o an o th e r , a d h e r i n gt od e f i n e dr u l e sa n d c o n s t r a i n t s. - Is o l a t i o ne n s u r e sth a tc o n c u r r e n tt r a n s a c t i o n s d on o ti n t e rf e r ewi the a c ho th e r , p r o v i d i n gal e v e l o fs e p a r at i o na n dp r e v e n t i n gd a t a i n c o n s i s t e n c i e s. - D u r a b i l i t ye n s u r e sth a to n c eat r an s a c t i o ni s c o m m i t t e d, i t sc h a n g e sa r ep e r m a n e n tl ys a v e d an dwi l ls u rv i v ea n ys u b s e q u e n ts y s t e mf a i l u r e s.

  12. T h a n k sf o rr e a d i n g !

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