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[์ •๋ณด์ฒ˜๋ฆฌ๊ธฐ์‚ฌ] ์‹ค๊ธฐ ํ”„๋กœ๊ทธ๋ž˜๋ฐ์–ธ์–ด 3๋ฌธ์ œ (21)

by Sun A 2024. 10. 3.

1๏ธโƒฃ [SQL]

2021.2ํšŒ

๋‹ค์Œ์€ '์ด'์”จ ์„ฑ์„ ๊ฐ€์ง„ ์‚ฌ๋žŒ์˜ ์ด๋ฆ„์„ ๋‚ด๋ฆผ์ฐจ์ˆœ์œผ๋กœ ์ถœ๋ ฅํ•˜๊ธฐ ์œ„ํ•œ SQL๋ฌธ์ด๋‹ค. ๊ด„ํ˜ธ์•ˆ์— ๋“ค์–ด๊ฐˆ ์•Œ๋งž์€ ๋‹ต์•ˆ์„ ์ž‘์„ฑํ•˜์‹œ์˜ค.


  
SELECT ... FROM ... WHERE ์ด๋ฆ„ LIKE ( A ) ORDER BY ( B )
(A) '์ด%'
(B) ์ด๋ฆ„ DESC

 

2๏ธโƒฃ [SQL]

2020.3ํšŒ

๋‹ค์Œ ํ•™์ƒ ํ…Œ์ด๋ธ”์—์„œ ์ด๋ฆ„์ด ๋ฏผ์ˆ˜์ธ ํŠœํ”Œ์„ ์‚ญ์ œํ•˜๋„๋ก ๊ฒฐ๊ณผ๋ฅผ ์ž‘์„ฑํ•˜์‹œ์˜ค.


  
- ํ…Œ์ด๋ธ”๋ช…: ํ•™์ƒ
- ํ•„๋“œ๋ช…: ์ด๋ฆ„
DELETE
FROM ํ•™์ƒ
WHERE ์ด๋ฆ„ = '๋ฏผ์ˆ˜';

 

3๏ธโƒฃ [JAVA]

2023.2ํšŒ

๋‹ค์Œ์€ ์ž๋ฐ” ํ”„๋กœ๊ทธ๋ž˜๋ฐ์— ๋Œ€ํ•œ ๋ฌธ์ œ์ด๋‹ค. ์•Œ๋งž์€ ์ถœ๋ ฅ๊ฐ’์„ ์ž‘์„ฑํ•˜์‹œ์˜ค. ๋‹จ, ํ”„๋กœ๊ทธ๋ž˜๋ฐ ์–ธ์–ด ํŠน์„ฑ์— ๋”ฐ๋ฅธ ๋Œ€ยท์†Œ๋ฌธ์ž๋ฅผ ๋ฐ˜๋“œ์‹œ ๊ตฌ๋ณ„ํ•ด์„œ ์ž‘์„ฑํ•˜์‹œ์˜ค.


  
public class Main{
public static void main(String[] args) {
String str1 = 'Programming';
String str2 = 'Programming';
String str3 = new String('Programming');
println(str1==str2)
println(str1==str3)
println(str1.equals(str3))
print(str2.equals(str3))
}
}
true
false
true
true

str1๊ณผ str2๋Š” ๊ฐ™์€ ๋ฉ”๋ชจ๋ฆฌ ์ฃผ์†Œ์— ๊ฐ’์ด ์ €์žฅ๋˜์–ด์žˆ๊ธฐ ๋•Œ๋ฌธ์— ๊ฐ™๋‹ค.

ํ•˜์ง€๋งŒ str3๋Š” ์ƒˆ๋กœ์šด ๋ฉ”๋ชจ๋ฆฌ์— ์ƒˆ๋กœ ์ €์žฅ๋˜์—ˆ๊ธฐ ๋•Œ๋ฌธ์— str1๊ณผ ์ฃผ์†Œ๊ฐ’์ด ๋‹ฌ๋ผ์„œ false๊ฐ€ ๋‚˜์˜จ๋‹ค.

๋ฐ‘์˜ equals๋Š” ์ฃผ์†Œ๊ฐ’์ด ์•„๋‹Œ ๋‘ ๋ฌธ์ž์—ด์ด ๊ฐ™์€์ง€์— ๋Œ€ํ•ด ๋ฌป๋Š” ๊ฒƒ์ด๊ธฐ ๋•Œ๋ฌธ์— ๋‘˜๋‹ค true๊ฐ€ ๋ฐ˜ํ™˜๋œ๋‹ค.

* ์ฐธ/๊ฑฐ์ง“ : C์–ธ์–ด - 1/0, JAVA - true/false, Python - True/False