๐Ÿ–ฅ๏ธ ์ฝ”๋”ฉํ…Œ์ŠคํŠธ/SQL

[ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค] [SQL] ํ•œ ํ•ด์— ์žก์€ ๋ฌผ๊ณ ๊ธฐ ์ˆ˜ ๊ตฌํ•˜๊ธฐ

rtw0202 2026. 2. 17. 12:32

1. ๋ฌธ์ œ ์„ค๋ช…

๋‚š์‹œ์•ฑ์—์„œ ์‚ฌ์šฉํ•˜๋Š” FISH_INFO ํ…Œ์ด๋ธ”์€ ์žก์€ ๋ฌผ๊ณ ๊ธฐ๋“ค์˜ ์ •๋ณด๋ฅผ ๋‹ด๊ณ  ์žˆ์Šต๋‹ˆ๋‹ค. FISH_INFO ํ…Œ์ด๋ธ”์˜ ๊ตฌ์กฐ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์œผ๋ฉฐ ID, FISH_TYPE, LENGTH, TIME์€ ๊ฐ๊ฐ ์žก์€ ๋ฌผ๊ณ ๊ธฐ์˜ ID, ๋ฌผ๊ณ ๊ธฐ์˜ ์ข…๋ฅ˜(์ˆซ์ž), ์žก์€ ๋ฌผ๊ณ ๊ธฐ์˜ ๊ธธ์ด(cm), ๋ฌผ๊ณ ๊ธฐ๋ฅผ ์žก์€ ๋‚ ์งœ๋ฅผ ๋‚˜ํƒ€๋ƒ…๋‹ˆ๋‹ค.

๋‹จ, ์žก์€ ๋ฌผ๊ณ ๊ธฐ์˜ ๊ธธ์ด๊ฐ€ 10cm ์ดํ•˜์ผ ๊ฒฝ์šฐ์—๋Š” LENGTH ๊ฐ€ NULL ์ด๋ฉฐ, LENGTH ์— NULL ๋งŒ ์žˆ๋Š” ๊ฒฝ์šฐ๋Š” ์—†์Šต๋‹ˆ๋‹ค.

FISH_INFO ํ…Œ์ด๋ธ”์—์„œ 2021๋…„๋„์— ์žก์€ ๋ฌผ๊ณ ๊ธฐ ์ˆ˜๋ฅผ ์ถœ๋ ฅํ•˜๋Š” SQL ๋ฌธ์„ ์ž‘์„ฑํ•ด์ฃผ์„ธ์š”. ์ด ๋•Œ ์ปฌ๋Ÿผ๋ช…์€ 'FISH_COUNT' ๋กœ ์ง€์ •ํ•ด์ฃผ์„ธ์š”.


2. ์ถœ๋ ฅ ์˜ˆ์‹œ

 
3. ๋ฌธ์ œ ๋‹ต์•ˆ

SELECT 
 COUNT(id) as fish_count
FROM fish_info
WHERE time >= '2021-01-01' AND
      time < '2022-01-01'