IS NULL
์ฐ์ฐ์๋ ๋ฐ์ดํฐ ๊ฐ์ด null์ธ ๊ฒฝ์ฐ๋ฅผ ์กฐํํ๊ณ ์ ํ ๋ ์ฌ์ฉํ๋ค.
๐ก null์ 0์ด๋ ๊ณต๋ฐฑ(space)๊ณผ๋ ์์ฐํ ๋ค๋ฆ! 0์ ์ซ์ ๊ฐ์ด๊ณ ๊ณต๋ฐฑ์ ๋ฌธ์ ๊ฐ์ด๋ฏ๋ก ๋ค๋ฅธ ์ ํ์ ๋ฐ์ดํฐ ๊ฐ์ด๋ค!
SELECT
"ํ๋๋ช "
FROM
"ํ ์ด๋ธ๋ช "
WHERE
"ํ๋๋ช " IS NULL
SELECT
"ํ๋๋ช "
FROM
"ํ ์ด๋ธ๋ช "
WHERE
"ํ๋๋ช " IS NOT NULL
SELECT ANIMAL_ID
FROM ANIMAL_INS
WHERE NAME IS NULL
ORDER BY ANIMAL_ID
SELECT ANIMAL_ID
FROM ANIMAL_INS
WHERE NAME IS NOT NULL
ORDER BY ANIMAL_ID ASC
SELECT ANIMAL_TYPE, IFNULL(NAME,"No name") AS NAME, SEX_UPON_INTAKE
FROM ANIMAL_INS
ORDER BY ANIMAL_ID
IFNULL
์ ์ฌ์ฉํด NULL์ผ๋๋ฅผ ์ฒ๋ฆฌํด์ค๋ค