vn_num     vs_string 中合并拼接的变量数量

SELECT SUBSTR(vs_string,
              DECODE(LEVEL,1,0,(INSTR(vs_string,',',1,LEVEL-1)))+1,
              DECODE(LEVEL,vn_num,LENGTH(vs_string),INSTR(vs_string,',',1,DECODE(LEVEL,1,1,LEVEL))-1)-
              (DECODE(LEVEL,1,0,(INSTR(vs_string,',',1,LEVEL-1)))+1)+1)
              FROM DUAL
              CONNECT BY LEVEL <= (SELECT REGEXP_COUNT(vs_string,',',1,'i')+1 FROM DUAL);
             

在oracle 中 IN 函数只能对查询的结果集或明确的参数集合进行多行查询，对于一个参数无论其表现形式只能进行一个参数的判断查询

如

EMPLOYEE_T 表中存在如下数据

EMPLOYEE_ID        EMPLOYEE_NAME
--------------------------------
001                 znp
002                 zsj
003                 zhsj

SELECT EMPLOYEE_ID,EMPLOYEE_NAME FROM EMPLOYEE_T WHERE EMPLOYEE_ID IN ('001','002')的查询结果如下

EMPLOYEE_ID        EMPLOYEE_NAME
--------------------------------
001                 znp
002                 zsj

SELECT EMPLOYEE_ID,EMPLOYEE_NAME FROM EMPLOYEE_T WHERE EMPLOYEE_ID IN ('001,002')的查询结果如下

EMPLOYEE_ID        EMPLOYEE_NAME
--------------------------------

在 SELECT * FROM EMPLOYEE_T WHERE EMPLOYEE_ID IN ('001,002') 中 "'001,002'" 只能做为一个入参而不是两个入参,参数值为
'001,002' ,故查不到合适的记录

在存储过程中对于以上的入参可以采取两种办法进行

1、通过拼接动态SQL进行查询

vs_sql := 'SELECT EMPLOYEE_ID,EMPLOYEE_NAME FROM EMPLOYEE_T WHERE EMPLOYEE_ID IN ('||CHR(39)||'001'||CHR(39)||','||CHR(39)||'002'||CHR(39)||');

OPEN _cur FOR vs_sql;

2、将拼接串转为结果集输出至IN函数中,使用如下脚本

vs_string  输入参数格式如'info1,info22,info333,info4444',以","做间隔符,每变量长度不确定

vn_num     vs_string 中合并拼接的变量数量

SELECT SUBSTR(vs_string,
              DECODE(LEVEL,1,0,(INSTR(vs_string,',',1,LEVEL-1)))+1,
              DECODE(LEVEL,vn_num,LENGTH(vs_string),INSTR(vs_string,',',1,DECODE(LEVEL,1,1,LEVEL))-1)-
              (DECODE(LEVEL,1,0,(INSTR(vs_string,',',1,LEVEL-1)))+1)+1)
              FROM DUAL
              CONNECT BY LEVEL <= (SELECT REGEXP_COUNT(vs_string,',',1,'i')+1 FROM DUAL);
             
照办上例,即为

SELECT EMPLOYEE_ID,EMPLOYEE_NAME FROM EMPLOYEE_T
                                 WHERE EMPLOYEE_ID IN
                                 (
                                      SELECT SUBSTR(vs_string,
                                             DECODE(LEVEL,1,0,(INSTR(vs_string,',',1,LEVEL-1)))+1,
                                             DECODE(LEVEL,vn_num,LENGTH(vs_string),INSTR(vs_string,',',1,DECODE(LEVEL,1,1,LEVEL))-1)-
                                             (DECODE(LEVEL,1,0,(INSTR(vs_string,',',1,LEVEL-1)))+1)+1)
                                             FROM DUAL
                                             CONNECT BY LEVEL <= (SELECT REGEXP_COUNT(vs_string,',',1,'i')+1 FROM DUAL)
                                 );