๊ด€๋ฆฌ ๋ฉ”๋‰ด

๋ชฉ๋กquery (1)

๋š๋”ฑ๊ฐœ๋ฐœ ๐Ÿ”จ

[MySQL] SELECT WHERE์ ˆ ์กฐ๊ฑด์˜ ๊ฒฐ๊ณผ๊ฐ€ ์—†์œผ๋ฉด INSERT ํ•˜๊ธฐ

stu_class : ํ•™์ƒ๊ณผ ํ•™๊ธ‰์— ๋Œ€ํ•œ ์ •๋ณด ํ…Œ์ด๋ธ” (ํ•™์ƒ์€ ์—ฌ๋Ÿฌ๊ฐœ์˜ ํ•™๊ธ‰์„ ๊ฐ€์งˆ ์ˆ˜ ์žˆ๋‹ค) stu_code : ํ•™์ƒ ์ฝ”๋“œ class_code : ํ•™๊ธ‰ ์ฝ”๋“œ ํ•™๊ธ‰์— ํ•™์ƒ์„ ๋ฐฐ์ •ํ•˜๊ธฐ ์ „, ํ•ด๋‹น ํ•™๊ธ‰์— ํ•™์ƒ์ด ์ด๋ฏธ ์†Œ์†๋˜์–ด ์žˆ๋Š”์ง€ ํ™•์ธํ•˜๊ณ  ์ค‘๋ณต ์‚ฝ์ž…์„ ๋ง‰์œผ๋ ค๊ณ  ์•„๋ž˜์ฒ˜๋Ÿผ ์†Œ์Šค๋ฅผ ์งฐ๋‹ค. 1. ํ•™๊ธ‰, ํ•™์ƒ ๊ฐ๊ฐ ์ฝ”๋“œ ๊ฐ’์œผ๋กœ stu_class ํ…Œ์ด๋ธ” ์กฐํšŒ 2. ๊ฒฐ๊ณผ๊ฐ’์ด ์žˆ์œผ๋ฉด ์ค‘๋ณต ๋ฐฐ์ • ๋ง‰๊ธฐ, ์—†์œผ๋ฉด ํ•™๊ธ‰ ๋ฐฐ์ • ์‹ค์ œ ์†Œ์Šค๋Š” select ์ฟผ๋ฆฌ ์กฐํšŒ ์‹คํŒจํ–ˆ์„ ๋•Œ.. ์กฐํšŒ ๊ฒฐ๊ณผ ์žˆ์œผ๋ฉด?..์—†์œผ๋ฉด?..insertํ•ด.. if๋ฌธ์˜ ์—ฐ์†๐Ÿ˜” if๋ฌธ ๋ฒ„๋ฆฌ๊ณ  ์ฟผ๋ฆฌ๋กœ ํ•œ๋ฐฉ์— ํ•ด๊ฒฐํ•ด๋ณด๊ธฐ๋กœ ํ•จ๐Ÿ‘INSERT INTO stu_class (stu_code, class_code) SELECT 2, 3 FROM DUAL WHERE NOT EXI..

DB/๐Ÿฌ MySQL 2023. 11. 22. 23:29