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๐Ÿ’พ ๋ฐ์ดํ„ฐ๋ฒ ์ด์Šค
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์•ˆ๋…•ํ•˜์„ธ์š”,. AI & ๋ฐ์ดํ„ฐ๋ถ„์„์„ ์ „๊ณตํ•˜๋Š” ๋Œ€ํ•™์›์ƒ ์ž…๋‹ˆ๋‹ค!
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์ตœ๊ทผ ๋Œ“๊ธ€
๐Ÿ“ŒSQL ๋ฌธ๋ฒ• - ํ…Œ์ด๋ธ” ๊ตฌ์กฐ ์ˆ˜์ •๊ณผ ๋ฐ์ดํ„ฐ ์กฐ์ž‘์ด๋ฏธ ๋งŒ๋“ค์–ด์ง„ ํ…Œ์ด๋ธ”์„ ์ˆ˜์ •, ์‚ญ์ œํ•˜๊ฑฐ๋‚˜๊ทธ ์•ˆ์˜ ๋ฐ์ดํ„ฐ๋ฅผ ์‚ฝ์ž…, ์ˆ˜์ •, ์‚ญ์ œํ•˜๋Š” ๋ฐฉ๋ฒ•์„ ์ •๋ฆฌํ•ด๋ณด๊ฒ ์Šต๋‹ˆ๋‹ค. (ALTER, DROP, INSERT, UPDATE, DELETE)
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a year ago
6 min read
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๐Ÿ“ŒSQL ๋ฌธ๋ฒ• - ํ…Œ์ด๋ธ” ์ƒ์„ฑ(CREATE TABLE)๊ณผ ์ œ์•ฝ์กฐ๊ฑด(Constraint)๋ฐ์ดํ„ฐ๋ฅผ ์ €์žฅํ•˜๋ ค๋ฉด ๋จผ์ € ๊ทธ๋ฆ‡(ํ…Œ์ด๋ธ”)์„ ๋งŒ๋“ค์–ด์•ผ๊ฒ ์ฃ ? ์ด๋ฒˆ ๊ธ€์—์„œ๋Š” SQL์—์„œ ํ…Œ์ด๋ธ”์„ ์ƒ์„ฑ(CREATE)ํ•˜๋Š” ๋ฐฉ๋ฒ•๊ณผ, ์ œ์•ฝ ์กฐ๊ฑด(Constraint)์„ ํ†ตํ•ด ๋ฐ์ดํ„ฐ๋ฅผ ์•ˆ์ „ํ•˜๊ฒŒ ๊ด€๋ฆฌํ•˜๋Š” ๋ฒ•์„ ์ •๋ฆฌํ•ด๋ณด๊ฒ ์Šต๋‹ˆ๋‹ค!
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a year ago
10 min read
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๐Ÿ“ŒSQL ๋ฌธ๋ฒ• - UNION๊ณผ ์ง‘ํ•ฉ ์—ฐ์‚ฐ ํ™œ์šฉ๋ฒ•SQL์€ ๋‹จ์ˆœํžˆ ํ…Œ์ด๋ธ”์—์„œ ๋ฐ์ดํ„ฐ๋ฅผ ์กฐํšŒํ•˜๋Š” ๊ฒƒ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ, ์—ฌ๋Ÿฌ ์ฟผ๋ฆฌ ๊ฒฐ๊ณผ๋ฅผ ์กฐํ•ฉํ•˜๊ฑฐ๋‚˜ ๋น„๊ตํ•˜๋Š” ๊ฒƒ๋„ ๊ฐ€๋Šฅํ•ฉ๋‹ˆ๋‹ค. ์ด๋ฒˆ ๊ธ€์—์„œ๋Š” SQL์˜ ์ง‘ํ•ฉ ์—ฐ์‚ฐ์ž๋“ค์„ ์ •๋ฆฌํ•ด๋ณด๊ฒ ์Šต๋‹ˆ๋‹ค.
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a year ago
9 min read
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๐Ÿ“ŒSQL ๋ฌธ๋ฒ• - ์„œ๋ธŒ์ฟผ๋ฆฌ(Subquery)์„œ๋ธŒ์ฟผ๋ฆฌ๋Š” SQL ์ฟผ๋ฆฌ ์•ˆ์— ๋˜ ๋‹ค๋ฅธ ์ฟผ๋ฆฌ๊ฐ€ ๋“ค์–ด์žˆ๋Š” ํ˜•ํƒœ๋ฅผ ๋งํ•ฉ๋‹ˆ๋‹ค. ์‚ฌ์šฉ์˜ˆ์ œ์™€ ํ•จ๊ป˜ ์„œ๋ธŒ์ฟผ๋ฆฌ์— ๋Œ€ํ•ด ์•Œ์•„๋ด…์‹œ๋‹ค.
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a year ago
8 min read
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๐Ÿ“ŒSQL ๋ฌธ๋ฒ• - ์กฐ์ธ(JOIN)๊ด€๊ณ„ํ˜• ๋ฐ์ดํ„ฐ๋ฒ ์ด์Šค์˜ ๊ฐ€์žฅ ํฐ ์žฅ์ ์€ ํ…Œ์ด๋ธ”์„ ๋‚˜๋ˆ  ์„ค๊ณ„ํ•˜๊ณ ,ํ•„์š”ํ•  ๋•Œ ์กฐ์ธ(JOIN) ์œผ๋กœ ์—ฐ๊ฒฐํ•ด ์›ํ•˜๋Š” ๋ฐ์ดํ„ฐ๋ฅผ ๊ฐ€์ ธ์˜ฌ ์ˆ˜ ์žˆ๋‹ค๋Š” ๊ฒƒ!์ด๋ฒˆ ๊ธ€์—์„œ๋Š” INNER JOIN, OUTER JOIN, NATURAL JOIN ๋“ฑ์˜ ๊ฐœ๋…์„ ์ •๋ฆฌํ•ด๋ณด๊ฒ ์Šต๋‹ˆ๋‹ค.
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a year ago
9 min read
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๐Ÿ“ŒSQL ๋ฌธ๋ฒ• - GROUP BY & HAVING ๊ตฌ๋ถ„ํ•˜๊ธฐSQL์—์„œ ๋ฐ์ดํ„ฐ๋ฅผ ์ง‘๊ณ„ํ•  ๋•Œ ๊ผญ ๋“ฑ์žฅํ•˜๋Š” ๋‘ ์นœ๊ตฌ, GROUP BY ์™€ HAVING. ์ด ๋‘˜์€ ํ•จ๊ป˜ ์“ฐ์ด์ง€๋งŒ, ์—ญํ• ์ด ์™„์ „ํžˆ ๋‹ค๋ฆ…๋‹ˆ๋‹ค.์ด๋ฒˆ ๊ธ€์—์„œ๋Š” ๋‘ ๋ฌธ๋ฒ•์„ ์•Œ์•„๋ด…์‹œ๋‹ค.
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a year ago
7 min read
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๐Ÿ“ŒSQL ๋ฌธ๋ฒ• - ORDER BY ์ ˆ๋กœ ์ •๋ ฌํ•˜๊ธฐ SQL์—์„œ ์ •๋ ฌ์€ ORDER BY ์ ˆ์„ ์‚ฌ์šฉํ•ด์„œ ์ฒ˜๋ฆฌํ•ฉ๋‹ˆ๋‹ค. ORDER BY๋Š” SELECT ๊ฒฐ๊ณผ๋ฅผ ํŠน์ • ์ปฌ๋Ÿผ ๊ธฐ์ค€์œผ๋กœ ์ •๋ ฌํ•  ๋•Œ ์‚ฌ์šฉํ•˜๋Š” ์ ˆ์ž…๋‹ˆ๋‹ค. ORDER BY์ ˆ์˜ ์‚ฌ์šฉ์— ๋Œ€ํ•ด ์•Œ์•„๋ด…์‹œ๋‹ค!
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a year ago
5 min read
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๐Ÿ“ŒSQL ๋ฌธ๋ฒ• - ์ง‘๊ณ„ ํ•จ์ˆ˜(Aggregation Functions)์™€ ๋ฐ์ดํ„ฐ๋ฅผ ์š”์•ฝ๋ฐ์ดํ„ฐ๊ฐ€ ๋งŽ์„์ˆ˜๋ก ์ „์ฒด ๋‚ด์šฉ์„ ์š”์•ฝํ•ด์„œ ํŒŒ์•…ํ•˜๋Š” ๊ฒŒ ์ค‘์š”ํ•ฉ๋‹ˆ๋‹ค. ์ด๋Ÿด ๋•Œ ์‚ฌ์šฉํ•˜๋Š” ๊ฒƒ์ด ๋ฐ”๋กœ ์ง‘๊ณ„ ํ•จ์ˆ˜(Aggregation Functions)! ์ง‘๊ณ„ํ•จ์ˆ˜์— ๋Œ€ํ•ด ์•Œ์•„๋ด…์‹œ๋‹ค.
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a year ago
7 min read
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๐Ÿ“ŒSQL ๋ฌธ๋ฒ• - WHERE ์ ˆ ์กฐ๊ฑด๋ฌธsql ๊ธฐ๋ณธ ๋ฌธ๋ฒ•์ธ where์ ˆ ์กฐ๊ฑด๋ฌธ์— ๋Œ€ํ•ด ์•Œ์•„๋ด…์‹œ๋‹ค!
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a year ago
8 min read
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๐Ÿ“ŒSQL ๋ฌธ๋ฒ• - SELECT ๋ฌธ ๊ธฐ๋ณธ ๊ตฌ์กฐSQL๋ฌธ๋ฒ•์˜ ๊ธฐ๋ณธ, select๋ฌธ
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a year ago
10 min read
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๊ด€๊ณ„ ๋Œ€์ˆ˜(Relational Algebra)๊ด€๊ณ„ํ˜• ๋ฐ์ดํ„ฐ๋ฒ ์ด์Šค(Relational Database)์˜ ํ•ต์‹ฌ ๊ฐœ๋…์ธ ๊ด€๊ณ„ ๋Œ€์ˆ˜(Relational Algebra)์™€ ๊ทธ ์ „์ œ ๊ฐœ๋…๋“ค์„ ์ •๋ฆฌํ•ฉ๋‹ˆ๋‹ค.๐Ÿ“Œ ๊ด€๊ณ„(Relation)์˜ ๊ฐœ๋…โœ… ๊ตฌ์„ฑ ์š”์†Œ์Šคํ‚ค๋งˆ(Schema): ํ…Œ์ด๋ธ” ๊ตฌ์กฐ ์ •์˜.์˜ˆ) ๋„์„œ(๋„์„œ๋ฒˆํ˜ธ, ๋„์„œ์ด๋ฆ„, ์ถœํŒ์‚ฌ, ๊ฐ€๊ฒฉ)์ธ์Šคํ„ด์Šค(Instance): ์‹ค์ œ ๋ฐ์ดํ„ฐ.ํŠœํ”Œ(Tuple): ํ•œ ํ–‰(Row)
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a year ago
22 min read
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๐Ÿ’พ ๋ฐ์ดํ„ฐ๋ฒ ์ด์Šค๋ž€?์šฐ๋ฆฌ๋Š” ๋งค์ผ ๋‹ค์–‘ํ•œ ์ •๋ณด๋ฅผ ์ €์žฅํ•˜๊ณ , ๊บผ๋‚ด๊ณ , ๊ด€๋ฆฌํ•ฉ๋‹ˆ๋‹ค.์ด๋Ÿฐ ์ •๋ณด๋“ค์„ ์ฒด๊ณ„์ ์œผ๋กœ ๋‹ค๋ฃจ๊ธฐ ์œ„ํ•ด ํ•„์š”ํ•œ ๊ฒƒ์ด ๋ฐ”๋กœ ๋ฐ์ดํ„ฐ๋ฒ ์ด์Šค(Database) ์ž…๋‹ˆ๋‹ค.๐Ÿ“Œ ๋ฐ์ดํ„ฐ๋ฒ ์ด์Šค๋ž€?๋ฐ์ดํ„ฐ๋ฒ ์ด์Šค(Database) ๋Š”"์—ฌ๋Ÿฌ ์‚ฌ๋žŒ๋“ค์ด ๊ณต์œ ํ•˜๊ณ  ์‚ฌ์šฉํ•  ๋ชฉ์ ์œผ๋กœ ํ†ตํ•ฉํ•˜์—ฌ ์ €์žฅํ•œ ๋ฐ์ดํ„ฐ์˜ ์ง‘ํ•ฉ"์‰ฝ๊ฒŒ ๋งํ•ด,ํ•„์š”ํ•œ ์ •๋ณด๋ฅผ ์ฒด๊ณ„์ ์œผ๋กœ ๋ชจ์•„๋‘๊ณ , ํšจ์œจ์ ์œผ๋กœ ๊บผ๋‚ด ์“ธ ์ˆ˜ ์žˆ๋„๋ก ๋งŒ๋“  ์ €
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a year ago
6 min read
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์•„์ง ํƒœ๊ทธ๊ฐ€ ์—†์–ด์š”
์•„์ง ๋Œ“๊ธ€์ด ์—†์–ด์š”