ORACLE查询语句入门

查询基础

SELECT (显示内容)
FROM   (哪里查)
WHERE  (约束条件)

常用的查询

SELECT [DISTINCT]
    t1.column_1 [AS  `description`]
    ,t2.column_2 [AS  `description`]
    ,t1.column_1 *t2.column_12
    ,nvl(expr1,expr2)
    ,(CASE   
           WHEN condition1= '2G69'  
             THEN 'description1'  
           WHEN condition2= '2G88' OR condition4= '2G89'  
             THEN 'description2'  
           WHEN condition3 IS NULL  
             THEN 'description3'  
           ELSE  
             'description4'  
        END  
       ) t4 
       ,FUNCTION(...) 
    .......
FROM  table_name1 t1
    , table_name2 t2,
    ,(SELECT column_1 ...
           FROM table_name
           WHERE exists (...)
           ..... ) t3
WHERE expresion [NOT] LIKE pattern [ ESCAPE escape_characters ]
   AND  standard_cost BETWEEN 500 AND 600
   AND  standard_cost <> condition
   OR   expression [NOT] IN (v1,v2,...)
   OR  standard_cost = [ALL|ANY] (SELECT column_1 ...
           FROM table_name
           ..... )
INNER JOIN table_name3
GROUP BY col_name,... 
HAVING where_condition
ORDER BY
    column [ASC | DESC] [NULLS FIRST | NULLS LAST]
LIMIT offset,row_count
FETCH  NEXT [  row_count | percent PERCENT  ] ROWS  [ ONLY | WITH TIES ]；

递归使用

         START WITH：用于指定层次查询的起始根行，当然也可以指定末行开始查询
         CONNECT BY：用于指定父子行关系，在其后必须使用PRIOR引用父行
--递归层次显示11MP28440ZZZZ001110-004101的BOM结构
SELECT DISTINCT concat(lpad(' ',3*(level-1)),bmb01)   father_ima,
                concat(lpad(' ',3*(level+1-1)),bmb03) level_ima 
  FROM bmb_file,bma_file
 WHERE bma01=bmb01 AND bma10='2' AND bmb14='0'
 START WITH bmb01 = '11MP28440ZZZZ001110-004101' 
        AND bmb01 IS NOT NULL    AND bmb14='0'
        AND (bmb05 IS NULL OR bmb05>sysdate)
        AND bmb04<=sysdate
 CONNECT BY PRIOR bmb03 =  bmb01  --表示当前的bmb03是下阶的bmb01 
 ORDER BY father_ima DESC

INSERT 语句

INSERT INTO table_name VALUES (value1，value2，......);
INSERT INTO table_name(colum1，colum2，......) VALUES (value1，value2，......);
INSERT INTO table_name SELECT * FROM table_name2;

UPDATE语句

UPDATE table_name  
SET colum1=value1
,colum2=value2
..... 
WHERE condition