๋ณธ๋ฌธ ๋ฐ”๋กœ๊ฐ€๊ธฐ

๐Ÿ”ฅ PS(Problem Solving) ๐Ÿ”ฅ/SQL7

[SQL] Leetcode | 178. Rank Scores 178. Rank Scores Medium Rank Scores - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com ์ˆœ์œ„ ํ•จ์ˆ˜ DENSE_RANK() select score, `rank` from ( select score, DENSE_RANK() over (order by Score desc) as `rank` from Scores ) score_rank order by `rank`; 176 Second Highest Salary ๋ฅผ ํ’€๊ณ  ๋‚˜๋‹ˆ ์‰ฝ๊ฒŒ ํ’€ ์ˆ˜ ์žˆ๋˜.. 2021. 7. 8.
[SQL] Leetcode | 176. Second Highest Salary 176. Second Highest Salary Easy Second Highest Salary - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com ๋ฌธ์ œ ์ ‘๊ทผ ๋‘ ๋ฒˆ์งธ๋กœ ๋†’์€ ๊ธ‰์—ฌ๋ฅผ ์ถœ๋ ฅํ•˜๋Š” ๋ฌธ์ œ์˜€๋‹ค. ๋ฌธ์ œ๋Š”... ์‚ฌ๋žŒ์ด 2๋ช… ๋ฏธ๋งŒ์ผ ๋•Œ null์„ ๋ฐ˜ํ™˜ํ•ด์•ผ ํ•œ๋‹ค. ์ฒ˜์Œ ์ ‘๊ทผ ํ–ˆ๋˜ ๋ฐฉ๋ฒ•์€ limit, offset ์ด์—ˆ๋Š”๋ฐ, ์ด ๊ตฌ๋ฌธ์œผ๋กœ๋Š” ๋นˆ ๋ฐฐ์—ด์„ ๋ฐ˜ํ™˜ํ•œ๋‹ค. null์„ ๋ฐ˜ํ™˜ํ•˜๋ ค๋ฉด ํ•จ์ˆ˜๋ฅผ ๊ฑฐ์ณ์•ผ ํ•˜๋‚˜..? null ๋‹ค๋ฃจ๋Š” ๋ฐฉ๋ฒ•์„ ๋ชป์ฐพ๊ณ  Discuss ํƒญ์—์„œ ๋‹ค๋ฅธ ๋ฐฉ๋ฒ•.. 2021. 7. 7.
[SQL] ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค 7daySQL ์ฑŒ๋ฆฐ์ง€ Day 7 # ๋ฃจ์‹œ์™€ ์—˜๋ผ ์ฐพ๊ธฐ ํ…Œ์ด๋ธ” ๊ตฌ์กฐ ANIMAL_INS ํ…Œ์ด๋ธ”์€ ๋™๋ฌผ ๋ณดํ˜ธ์†Œ์— ๋“ค์–ด์˜จ ๋™๋ฌผ์˜ ์ •๋ณด๋ฅผ ๋‹ด์€ ํ…Œ์ด๋ธ”์ž…๋‹ˆ๋‹ค. ANIMAL_INS ํ…Œ์ด๋ธ” ๊ตฌ์กฐ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์œผ๋ฉฐ, ANIMAL_ID, ANIMAL_TYPE, DATETIME, INTAKE_CONDITION, NAME, SEX_UPON_INTAKE๋Š” ๊ฐ๊ฐ ๋™๋ฌผ์˜ ์•„์ด๋””, ์ƒ๋ฌผ ์ข…, ๋ณดํ˜ธ ์‹œ์ž‘์ผ, ๋ณดํ˜ธ ์‹œ์ž‘ ์‹œ ์ƒํƒœ, ์ด๋ฆ„, ์„ฑ๋ณ„ ๋ฐ ์ค‘์„ฑํ™” ์—ฌ๋ถ€๋ฅผ ๋‚˜ํƒ€๋ƒ…๋‹ˆ๋‹ค. NAME TYPE NULLABLE ANIMAL_ID VARCHAR(N) FALSE ANIMAL_TYPE VARCHAR(N) FALSE DATETIME DATETIME FALSE INTAKE_CONDITION VARCHAR(N) FALSE NAME VARCHAR(N) TRUE SEX_UPON_INTA.. 2019. 9. 9.
[SQL] ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค 7daySQL ์ฑŒ๋ฆฐ์ง€ Day 6 6์ผ์ฐจ์—๋Š” ๋‚ด์šฉ ๋ณต์Šต!! # ์˜ค๋žœ ๊ธฐ๊ฐ„ ๋ณดํ˜ธํ•œ ๋™๋ฌผ ํ…Œ์ด๋ธ” ๊ตฌ์กฐ ANIMAL_INS ํ…Œ์ด๋ธ”์€ ๋™๋ฌผ ๋ณดํ˜ธ์†Œ์— ๋“ค์–ด์˜จ ๋™๋ฌผ์˜ ์ •๋ณด๋ฅผ ๋‹ด์€ ํ…Œ์ด๋ธ”์ž…๋‹ˆ๋‹ค. ANIMAL_INS ํ…Œ์ด๋ธ” ๊ตฌ์กฐ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์œผ๋ฉฐ, ANIMAL_ID, ANIMAL_TYPE, DATETIME, INTAKE_CONDITION, NAME, SEX_UPON_INTAKE๋Š” ๊ฐ๊ฐ ๋™๋ฌผ์˜ ์•„์ด๋””, ์ƒ๋ฌผ ์ข…, ๋ณดํ˜ธ ์‹œ์ž‘์ผ, ๋ณดํ˜ธ ์‹œ์ž‘ ์‹œ ์ƒํƒœ, ์ด๋ฆ„, ์„ฑ๋ณ„ ๋ฐ ์ค‘์„ฑํ™” ์—ฌ๋ถ€๋ฅผ ๋‚˜ํƒ€๋ƒ…๋‹ˆ๋‹ค. NAME TYPE NULLABLE ANIMAL_ID VARCHAR(N) FALSE ANIMAL_TYPE VARCHAR(N) FALSE DATETIME DATETIME FALSE INTAKE_CONDITION VARCHAR(N) FALSE NAME VARCHAR(N) T.. 2019. 9. 7.
[SQL] ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค 7daySQL ์ฑŒ๋ฆฐ์ง€ Day 5 # ์—†์–ด์ง„ ๊ธฐ๋ก ์ฐพ๊ธฐ ํ…Œ์ด๋ธ” ๊ตฌ์กฐ ANIMAL_INS ํ…Œ์ด๋ธ”์€ ๋™๋ฌผ ๋ณดํ˜ธ์†Œ์— ๋“ค์–ด์˜จ ๋™๋ฌผ์˜ ์ •๋ณด๋ฅผ ๋‹ด์€ ํ…Œ์ด๋ธ”์ž…๋‹ˆ๋‹ค. ANIMAL_INS ํ…Œ์ด๋ธ” ๊ตฌ์กฐ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์œผ๋ฉฐ, ANIMAL_ID, ANIMAL_TYPE, DATETIME, INTAKE_CONDITION, NAME, SEX_UPON_INTAKE๋Š” ๊ฐ๊ฐ ๋™๋ฌผ์˜ ์•„์ด๋””, ์ƒ๋ฌผ ์ข…, ๋ณดํ˜ธ ์‹œ์ž‘์ผ, ๋ณดํ˜ธ ์‹œ์ž‘ ์‹œ ์ƒํƒœ, ์ด๋ฆ„, ์„ฑ๋ณ„ ๋ฐ ์ค‘์„ฑํ™” ์—ฌ๋ถ€๋ฅผ ๋‚˜ํƒ€๋ƒ…๋‹ˆ๋‹ค. NAME TYPE NULLABLE ANIMAL_ID VARCHAR(N) FALSE ANIMAL_TYPE VARCHAR(N) FALSE DATETIME DATETIME FALSE INTAKE_CONDITION VARCHAR(N) FALSE NAME VARCHAR(N) TRUE SEX_UPON_INTA.. 2019. 9. 6.
[SQL] ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค 7daySQL ์ฑŒ๋ฆฐ์ง€ Day 4 # ๊ณ ์–‘์ด์™€ ๊ฐœ๋Š” ๋ช‡ ๋งˆ๋ฆฌ ์žˆ์„๊นŒ ํ…Œ์ด๋ธ” ๊ตฌ์กฐ ANIMAL_INS ํ…Œ์ด๋ธ”์€ ๋™๋ฌผ ๋ณดํ˜ธ์†Œ์— ๋“ค์–ด์˜จ ๋™๋ฌผ์˜ ์ •๋ณด๋ฅผ ๋‹ด์€ ํ…Œ์ด๋ธ”์ž…๋‹ˆ๋‹ค. ANIMAL_INS ํ…Œ์ด๋ธ” ๊ตฌ์กฐ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์œผ๋ฉฐ, ANIMAL_ID, ANIMAL_TYPE, DATETIME, INTAKE_CONDITION, NAME, SEX_UPON_INTAKE๋Š” ๊ฐ๊ฐ ๋™๋ฌผ์˜ ์•„์ด๋””, ์ƒ๋ฌผ ์ข…, ๋ณดํ˜ธ ์‹œ์ž‘์ผ, ๋ณดํ˜ธ ์‹œ์ž‘ ์‹œ ์ƒํƒœ, ์ด๋ฆ„, ์„ฑ๋ณ„ ๋ฐ ์ค‘์„ฑํ™” ์—ฌ๋ถ€๋ฅผ ๋‚˜ํƒ€๋ƒ…๋‹ˆ๋‹ค. NAME TYPE NULLABLE ANIMAL_ID VARCHAR(N) FALSE ANIMAL_TYPE VARCHAR(N) FALSE DATETIME DATETIME FALSE INTAKE_CONDITION VARCHAR(N) FALSE NAME VARCHAR(N) TRUE SEX_UP.. 2019. 9. 5.
[SQL] ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค 7daySQL ์ฑŒ๋ฆฐ์ง€ Day 1~3 (๐Ÿ‘€) 7daySQL ์ฑŒ๋ฆฐ์ง€ (๐Ÿ‘€) ์ฝ”๋”ฉํ…Œ์ŠคํŠธ์— SQL๋ฌธ์ œ ๋น„์ค‘์ด ํ•ด๋งˆ๋‹ค ์ฆ๊ฐ€ํ•˜๋Š”๋ฐ, ์–ด๋–ป๊ฒŒ ์ค€๋น„ํ•˜๋ฉด ์ข‹์„๊นŒ์š”? ๐Ÿ’Ž ์ฐธ์—ฌ ๋ฐฉ๋ฒ• ๋ฐ ๊ฒฝํ’ˆ ์•ˆ๋‚ด ๐Ÿ’Ž ๐Ÿ“ ์ฐธ์—ฌ ๋ฐฉ๋ฒ• : SQL ๋ฌธ์ œํ’€๊ธฐ -> ์ถœ์„๋„์žฅ์ฐ๊ธฐ -> ๊ฐค๋Ÿญ์‹œ๋ฒ„์ฆˆ ์ž๋™ ์‘๋ชจ ๐Ÿ’Œ ์ฐธ์—ฌ ๊ธฐ๊ฐ„ : 19๋…„ 09์›” 02์ผ(์›”) - 19๋…„ 09์›” 08์ผ(์ผ) 7์ผ๊ฐ„ ๋งค์ผ๋งค์ผ ์ฐธ์—ฌ ํ•„์ˆ˜ ๐Ÿ‘ ๋‹น์ฒจ์ž ๋ฐœํ‘œ : 19๋…„ 09์›” 09์ผ(์›”) https://programmers.co.kr/events/7day-sql?utm_source=programmers&utm_medium=learn_7daySQL&utm_campaign=7daySQL 7daySQL ์ฑŒ๋ฆฐ์ง€ | ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค ์ฝ”๋”ฉํ…Œ์ŠคํŠธ์— SQL๋ฌธ์ œ ๋น„์ค‘์ด ํ•ด๋งˆ๋‹ค ์ฆ๊ฐ€ํ•˜๋Š”๋ฐ, ์–ด๋–ป๊ฒŒ ์ค€๋น„ํ•˜๋ฉด ์ข‹์„๊นŒ์š”? ์ด์ œ ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค์—์„œ SQL.. 2019. 9. 4.