DB2sql——insert all与insert first用法讲解与实例

1、建测试表 
 

    CREATE TABLE EDW_INT   
    (   
      AGMT_NO         VARCHAR2(40 BYTE)             NOT NULL,   
      AGMT_SUB_NO     VARCHAR2(4 BYTE)              NOT NULL,   
      NEED_REPAY_INT  NUMBER(22,2),   
      CURR_PERIOD     NUMBER(4)                     NOT NULL   
    );   
    CREATE TABLE EDW_INT_1   
    (   
      AGMT_NO         VARCHAR2(40 BYTE)             NOT NULL,   
      AGMT_SUB_NO     VARCHAR2(4 BYTE)              NOT NULL,   
      NEED_REPAY_INT  NUMBER(22,2),   
      CURR_PERIOD     NUMBER(4)                     NOT NULL   
    );   
    CREATE TABLE EDW_INT_2   
    (   
      AGMT_NO         VARCHAR2(40 BYTE)             NOT NULL,   
      AGMT_SUB_NO     VARCHAR2(4 BYTE)              NOT NULL,   
      NEED_REPAY_INT  NUMBER(22,2),   
      CURR_PERIOD     NUMBER(4)                     NOT NULL   
    );  


2、插入测试数据 
 

    INSERT INTO EDW_INT   
      (AGMT_NO, AGMT_SUB_NO, NEED_REPAY_INT, CURR_PERIOD)   
    VALUES   
      ('20003874', '2104', 3126.5, 7);   
    INSERT INTO EDW_INT   
      (AGMT_NO, AGMT_SUB_NO, NEED_REPAY_INT, CURR_PERIOD)   
    VALUES   
      ('20003874', '2104', 3290.76, 6);   
    INSERT INTO EDW_INT   
      (AGMT_NO, AGMT_SUB_NO, NEED_REPAY_INT, CURR_PERIOD)   
    VALUES   
      ('20003874', '2104', 3454.06, 5);   
    INSERT INTO EDW_INT   
      (AGMT_NO, AGMT_SUB_NO, NEED_REPAY_INT, CURR_PERIOD)   
    VALUES   
      ('20003874', '2104', 3616.41, 4);   
    INSERT INTO EDW_INT   
      (AGMT_NO, AGMT_SUB_NO, NEED_REPAY_INT, CURR_PERIOD)   
    VALUES   
      ('20017143', '2104', 2350.86, 0);   
    INSERT INTO EDW_INT   
      (AGMT_NO, AGMT_SUB_NO, NEED_REPAY_INT, CURR_PERIOD)   
    VALUES   
      ('20017143', '2104', 3566.55, 0);   
    INSERT INTO EDW_INT   
      (AGMT_NO, AGMT_SUB_NO, NEED_REPAY_INT, CURR_PERIOD)   
    VALUES   
      ('20018273', '2104', 1639.46, 0);   
    INSERT INTO EDW_INT   
      (AGMT_NO, AGMT_SUB_NO, NEED_REPAY_INT, CURR_PERIOD)   
    VALUES   
      ('20018273', '2104', 2080.49, 0);   
    COMMIT;  


3、insert all/first语句示例

(1)、insert all-不带条件 
 

    insert all   
    into edw_int_1(agmt_no,agmt_sub_no,need_repay_int,curr_period)   
    values(agmt_no,agmt_sub_no,need_repay_int,curr_period)   
    into edw_int_2(agmt_no,agmt_sub_no,curr_period)   
    values(agmt_no,'1234',curr_period)   
    select agmt_no,agmt_sub_no,need_repay_int,curr_period from edw_int;   
    commit;  


(2)、insert all-带条件 
 

    insert all   
    when curr_period=0 then    
    into edw_int_1(agmt_no,agmt_sub_no,need_repay_int,curr_period)   
    values(agmt_no,agmt_sub_no,need_repay_int,curr_period)   
    else  
    into edw_int_2(agmt_no,agmt_sub_no,need_repay_int,curr_period)   
    values(agmt_no,agmt_sub_no,need_repay_int,curr_period)   
    select agmt_no,agmt_sub_no,need_repay_int,curr_period from edw_int;   
    commit;  


(3)、insert first-带条件 
 

    insert first   
    when curr_period=0 then    
    into edw_int_1(agmt_no,agmt_sub_no,need_repay_int,curr_period)   
    values(agmt_no,agmt_sub_no,need_repay_int,curr_period)   
    when agmt_sub_no='2104' then   
    into edw_int_2(agmt_no,agmt_sub_no,need_repay_int,curr_period)   
    values(agmt_no,agmt_sub_no,need_repay_int,curr_period)   
    select agmt_no,agmt_sub_no,need_repay_int,curr_period from edw_int;   
    commit;  


4、数据结果查看 
 

    truncate table edw_int_1;   
    truncate table edw_int_2;   
    select * from edw_int;   
    select * from edw_int_1;   
    select * from edw_int_2;  


5、all与first的区别

all:不考虑先后关系，只要满足条件，就全部插入；

first:考虑先后关系，如果有数据满足第一个when条件又满足第二个when条件，则执行第一个then插入语句，第二个then就不插入第一个then已经插入过的数据了。

其区别也可描述为，all只要满足条件，可能会作重复插入；first首先要满足条件，然后筛选，不做重复插入。