{"id":4988,"date":"2022-03-17T14:10:46","date_gmt":"2022-03-17T05:10:46","guid":{"rendered":"https:\/\/www.skyer9.pe.kr\/wordpress\/?p=4988"},"modified":"2022-03-17T18:36:59","modified_gmt":"2022-03-17T09:36:59","slug":"mysql-%eb%82%b4%ec%9e%a5-%ed%95%a8%ec%88%98-%ec%a0%95%eb%a6%ac","status":"publish","type":"post","link":"https:\/\/www.skyer9.pe.kr\/wordpress\/?p=4988","title":{"rendered":"MySQL \ub0b4\uc7a5 \ud568\uc218 \uc815\ub9ac"},"content":{"rendered":"

MySQL \ub0b4\uc7a5 \ud568\uc218 \uc815\ub9ac<\/h1>\n

\uc218\ud559 \ud568\uc218<\/h2>\n

ABS, MOD, POW, SQRT<\/h3>\n
SELECT ABS(-100);\nSELECT MOD(14, 3), 14 % 3, 14 MOD 3; -- \ub098\uba38\uc9c0\nSELECT POW(3, 2), SQRT(16); -- \uc81c\uacf1, \uc81c\uacf1\uadfc<\/code><\/pre>\n
CEILING, FLOOR, ROUND<\/h3>\n
SELECT CEILING(3.7), FLOOR(3.7), ROUND(3.7); -- \uc62c\ub9bc, \ubc84\ub9bc, \ubc18\uc62c\ub9bc\nSELECT CEILING(3.789, 2), FLOOR(3.789, 2), ROUND(3.789, 2);<\/code><\/pre>\n
RAND, TRUNCATE<\/h3>\n
SELECT RAND(); - \ub79c\ub364\nSELECT TRUNCATE(1234.6789, 2), TRUNCATE(1234.6789, -2); -- \ubc84\ub9bc<\/code><\/pre>\n
\ubb38\uc790\uc5f4 \ud568\uc218<\/h2>\n
ASCII, CHAR<\/h3>\n
SELECT ASCII('A');\nSELECT CHAR(65);<\/code><\/pre>\n
BIT_LENGTH, CHAR_LENGTH, LENGTH (\ubb38\uc790\uc5f4 \uae38\uc774)<\/h3>\n
UTF8 \uc5d0\uc11c \ud55c\uae00\uc740 3\ubc14\uc774\ud2b8\uc785\ub2c8\ub2e4.
\nCHAR_LENGTH \ub294 \ubb38\uc790\uc758 \uac2f\uc218, LENGTH \ub294 \ubc14\uc774\ud2b8 \uc218\ub97c \ub098\ud0c0\ub0c5\ub2c8\ub2e4.<\/p>\n
SELECT BIT_LENGTH('abc'), CHAR_LENGTH('abc'), LENGTH('abc');\nSELECT BIT_LENGTH('\uac00\ub098\ub2e4'), CHAR_LENGTH('\uac00\ub098\ub2e4'), LENGTH('\uac00\ub098\ub2e4');<\/code><\/pre>\n
CONCAT, CONCAT_WS (\ubb38\uc790\uc5f4 \ud569\uce58\uae30)<\/h3>\n
CONCAT_WS \ub294 \uad6c\ubd84\uc790\ub97c \uc774\uc6a9\ud574 \ubb38\uc790\ub97c \ud569\uce69\ub2c8\ub2e4.<\/p>\n
SELECT CONCAT('2020', '01', '01');\nSELECT CONCAT_WS('-','2020', '01', '01');<\/code><\/pre>\n
INSTR (\ucc3e\uae30)<\/h3>\n
\ucc3e\ub294 \ubb38\uc790\uc5f4\uc774 \uc5c6\uc73c\uba74 0 \uc744 \ubc18\ud658\ud569\ub2c8\ub2e4.<\/p>\n
SELECT INSTR('abcd', 'b');<\/code><\/pre>\n
FORMAT, LPAD, RPAD, LTRIM, RTRIM, TRIM<\/h3>\n
3\uc790\ub9ac\ub9c8\ub2e4 \ucf64\ub9c8\ub97c \ucd94\uac00\ud574 \uc90d\ub2c8\ub2e4. \uc18c\uc218\uc810 2\uc790\ub9ac\uae4c\uc9c0 \ud45c\uc2dc\ud569\ub2c8\ub2e4.<\/p>\n
SELECT FORMAT(123456789.1234, 2);\nSELECT LPAD('1234', 6, '0'), RPAD('1234', 6, '0');\nSELECT LTRIM('   abc'), RTRIM('abc   '), TRIM('  abc  ');<\/code><\/pre>\n
\uacf5\ubc31\ubb38\uc790 \uc774\uc678 \ub2e4\ub978 \ubb38\uc790\ub3c4 TRIM \ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
SELECT TRIM(BOTH 'a' FROM 'aababaa');<\/code><\/pre>\n
LEFT, RIGHT, MID, LCASE, UCASE, LOWER, UPPER<\/h3>\n
SELECT LEFT('\uac00\ub098\ub2e4\ub77c\ub9c8\ubc14', 3), RIGHT('\uac00\ub098\ub2e4\ub77c\ub9c8\ubc14', 3);\nSELECT LCASE('aBcDe'), UCASE('aBcDe'); -- \ub300\ubb38\uc790, \uc18c\ubb38\uc790\nSELECT LOWER('aBcDe'), UPPER('aBcDe');\nSELECT MID('aBcDe', 2, 3); -- \ubb38\uc790\uc5f4, \uc2dc\uc791\uc704\uce58, \uac2f\uc218<\/code><\/pre>\n
REPLACE, SUBSTRING<\/h3>\n
SELECT REPLACE ('It is banana', 'banana', 'apple');\nSELECT SUBSTRING('abcdef', 3, 2);   -- \ubb38\uc790\uc5f4, \uc2dc\uc791\uc704\uce58, \uae38\uc774<\/code><\/pre>\n
SUBSTRING_INDEX<\/h3>\n
\ucc3e\ub294 \ubb38\uc790\uc5f4\uc774 n \ud68c \ub4f1\uc7a5\ud558\uba74 \uadf8 \uc774\ud6c4 \ubb38\uc790\uc5f4\uc744 \ubc84\ub9bd\ub2c8\ub2e4.
\nn \uc774 \ub9c8\uc774\ub108\uc2a4\uc774\uba74 \uc624\ub978\ucabd\uc5d0\uc11c \uc2dc\uc791\ud569\ub2c8\ub2e4.<\/p>\n
SELECT SUBSTRING_INDEX('aaa,bbb,ccc,ddd', ',', 2);\nSELECT SUBSTRING_INDEX('aaa,bbb,ccc,ddd', ',', -2);<\/code><\/pre>\n
\ub0a0\uc9dc<\/h2>\n
ADDDATE, SUBDATE, DATE_ADD, DATE_SUB<\/h3>\n
SELECT ADDDATE('2020-01-01', INTERVAL 31 DAY), SUBDATE('2020-01-01', INTERVAL 31 DAY);\nSELECT DATE_ADD('2020-01-01', INTERVAL -31 DAY), DATE_SUB('2020-01-01', INTERVAL 31 DAY);\n\nSELECT ADDDATE('2020-01-01', INTERVAL -1 HOUR);\nSELECT ADDDATE('2020-01-01', INTERVAL -1 MINUTE);\nSELECT ADDDATE('2020-01-01', INTERVAL -1 SECOND);<\/code><\/pre>\n
CURDATE, CURTIME, NOW, SYSDATE (\uc624\ub298, \ud604\uc7ac\uc2dc\uac04)<\/h3>\n
CURDATE, CURTIME \ub294 \ub0a0\uc9dc \ub610\ub294 \uc2dc\uac04\ub9cc \ubc18\ud658\ud569\ub2c8\ub2e4.
\nNOW, SYSDATE \ub294 \ub0a0\uc9dc+\uc2dc\uac04\uc744 \ubc18\ud658\ud569\ub2c8\ub2e4.<\/p>\n
SELECT CURDATE(), CURTIME(), NOW(), SYSDATE();<\/code><\/pre>\n
YEAR, MONTH, DAYOFMONTH, HOUR, MINUTE, SECOND, MICROSECOND<\/h3>\n
SELECT YEAR(NOW()), MONTH(NOW()), DAYOFMONTH(NOW()),\n       HOUR(NOW()), MINUTE(NOW()), SECOND(NOW()), MICROSECOND(NOW));<\/code><\/pre>\n
MONTHNAME, DAYNAME, DAYOFWEEK, WEEKDAY<\/h3>\n
SELECT MONTHNAME('20000721'); -- \uc601\uc5b4 \uc6d4\uc774\ub984\nSELECT DAYNAME('2001-06-22'); -- \uc601\uc5b4 \uc694\uc77c\uc774\ub984\nSELECT DAYOFWEEK('2003-03-21'); -- \uc694\uc77c \uc22b\uc790, \uc6d4\uc694\uc77c(0),\ud654\uc694\uc77c(1), ..., \uc77c\uc694\uc77c(6)\nSELECT WEEKDAY('2003-03-21'); -- same as DAYOFWEEK<\/code><\/pre>\n
DATE, TIME, DATEDIFF, TIMEDIFF<\/h3>\n
SELECT DATE(NOW()), TIME(NOW());\nSELECT DATEDIFF('2020-1-5', '2020-1-1'), TIMEDIFF('14:30:00', '06:30:00');\nSELECT DAYOFWEEK(NOW()), MONTHNAME(NOW()), DAYOFYEAR(NOW());\nSELECT LAST_DAY('2020-02-04'); -- \ud574\ub2f9\uc6d4\uc758 \ub9c8\uc9c0\ub9c9 \ub0a0\uc9dc\nSELECT TIME_TO_SEC('10:53:10');<\/code><\/pre>\n
DATE_FORMAT, CONVERT_TZ<\/h3>\n
SELECT DATE_FORMAT(NOW(),'%Y-%m-%d') FROM DUAL;\nSELECT DATE_FORMAT(NOW(),'%H:%i:%S') FROM DUAL;\n\nSELECT @@GLOBAL.TIME_ZONE, @@SESSION.TIME_ZONE;\nSELECT CONCAT_WS(' ', DATE_FORMAT(NOW(),'%H:%i:%S'), @@SESSION.TIME_ZONE) FROM DUAL;\n\nSELECT DATE_FORMAT(CONVERT_TZ(NOW(), 'UTC', 'Asia\/Seoul'),'%H:%i:%S') FROM DUAL;<\/code><\/pre>\n
\ub17c\ub9ac \ud568\uc218<\/h2>\n
IF, IFNULL<\/h3>\n
SELECT IF(a>1, 'A', 'B'); -- \uc870\uac74\uc2dd, \ucc38\uc77c\ub54c \ubc18\ud658\uac12, \uac70\uc9d3\uc77c\ub54c \ubc18\ud658\uac12\nSELECT IFNULL(a, 'ERR'); -- \uccab\ubc88\uc9f8\uac00 NULL \uc774\uba74 \ub450\ubc88\uc9f8 \uac12 \ubc18\ud658<\/code><\/pre>\n
\ud1b5\uacc4 \ud568\uc218<\/h2>\n
COUNT, AVG, SUM, MIN, MAX<\/h3>\n
SELECT COUNT(column), AVG(column), SUM(column), MIN(column), MAX(column);<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
MySQL \ub0b4\uc7a5 \ud568\uc218 \uc815\ub9ac \uc218\ud559 \ud568\uc218 ABS, MOD, POW, SQRT SELECT ABS(-100); SELECT MOD(14, 3), 14 % 3, 14 MOD 3; — \ub098\uba38\uc9c0 SELECT POW(3, 2), SQRT(16); — \uc81c\uacf1, \uc81c\uacf1\uadfc CEILING, FLOOR, ROUND SELECT CEILING(3.7), FLOOR(3.7), ROUND(3.7); — \uc62c\ub9bc, \ubc84\ub9bc, \ubc18\uc62c\ub9bc SELECT CEILING(3.789, 2), FLOOR(3.789, 2), ROUND(3.789, 2); RAND, TRUNCATE SELECT RAND(); – \ub79c\ub364 SELECT\u2026 Read More »<\/a><\/span><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[],"class_list":["post-4988","post","type-post","status-publish","format-standard","hentry","category-mysql"],"_links":{"self":[{"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/4988","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4988"}],"version-history":[{"count":7,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/4988\/revisions"}],"predecessor-version":[{"id":4997,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/4988\/revisions\/4997"}],"wp:attachment":[{"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4988"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4988"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4988"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}