- SELECT column_name(s) FROM table1 UNION ALL SELECT column_name(s) FROM table2; -> 두가지가 합쳐져서 행으로... 없음에는 null 허용 안함 한글 나오려면 DEFAULT CHARACTER SET UTF8 를 붙여준다. person id가 0(null)... 
- △배우 자주 사용되니 사용법 기억해둬야 IS NULL 연산자 NULL 아닌 값 출력 집합 연산자 UNION, UNION ALL, MINUS, INTTERSECT 각 SELECT문이 출력하려는 열 개수와 각 열의 자료형이 순서별로 일치해야... 
- --6번 select * from emp where comm is null and MGR is not null and job = 'MANAGER' and ename not like '_L%' union all select * from emp where comm is null and MGR is not null and job = 'CLERK... 
- dual UNION ALL SELECT 2 AS item_id, 'SQL' AS item_desc FROM dual ) SELECT item_id , item_desc , NULLIF(item_desc, 'ORACLE') AS new_item_desc FROM mydb item_desc 칼럼의 값이 'ORACLE'인 경우 NULL을 반환하고... 
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- SELECT empno, ename, sal FROM emp WHERE job = 'SALESMAN' UNION ALL SELECT null, null, sum(sal) FROM emp WHERE job = 'SALESMAN'; 
- (SALES_DATE, 'YYYYMM') = '202203' UNION ALL SELECT SALES_DATE , PRODUCT_ID , NULL AS USER_ID , SALES_AMOUNT FROM OFFLINE_SALE WHERE TO_CHAR(SALES_DATE, 'YYYYMM') = '202203' ) ORDER BY SALES_DATE, PRODUCT_ID, USER... 
- ... UNION ALL 집합연산 사용 시 동일 컬럼 갯수, 컬럼 타입을 넣어줘야 되는것과 같은 이치.. 구지... SELECT search_condition, CASE WHEN search_condition IS NULL THEN ' ' END FROM user_constraints; 단 NULL로 표기가 안되지만... 
- ... ㅠㅠ 예를 들어 rpt_name asst serial_no 1 RPT_ITM_MAT NULL DD2100941 이 결과값을 rpt_name asst serial_no 1... 됩니다 select * from ~~~~~ union all select * from ~~~~~ union all select * from ~~~~~ union all select * from ~~~~~ 
- ... UNION ALL? 활용방법? 일반 리스트 쿼리입니다. SELECT * FROM ( SELECT ROW_NUMBER() OVER (ORDER BY NO) AS NUM, NO... THEN NULL ELSE UDATE END AS UDATE, HIT FROM (SELECT NO, DIF, TITLE, CONTENTS, ID, "DATE" AS IDATE, UDATE, HIT FROM SBOARD... 
- ... 7를 사용하여 WITH recursive cte AS ( SELECT cateName, cateCode, cateCodeRef, 1 AS level FROM goods_category WHERE cateCodeRef IS null UNION all SELECT p.cateName, p.cateCode, p.cateCodeRef, 1 + LEVEL AS level FROM goods... 
- ... 현재는 Select b.name, a.id From student a, profile b Where a.id = b.id And b.grade = ‘1’ Union all Select count(*) From... count를 to_char 처리하고 필드하나를 null 값으로 반환하는 후행쿼리를 작성해야겠죠.. 
- ... SELECT CASE WHEN TRIM(ANULL) IS NULL THEN BNULL ELSE BNULL END AS NULLCHECKCOL FROM ( Select *,a.null check 컬럼 as ANULL,' ' AS BNULL from a Union all Select *,' ' AS ANULL,b.null check 컬럼 AS BNULL from b ) A 이렇게...