Question

我想检查varchar是否包含另一个，像这样： str1 ='1,2,3,4' str2 ='2,1'

检查str2是否在str1中。在这个例子中，它是，因为str1同时具有1和2。我必须从java中调用一个简单的选择... 在java中我有字符串，我需要检查oracle中记录中的字符串是否在字符串中 - 但所有这些都在一个简单的选择中！

谢谢你！

Answer 1

You can create a simple function to split the delimited strings into collections and then use the SUBMULTISET operator to compare them. Like this:

Oracle Setup:

CREATE TYPE VARCHAR2_TABLE AS TABLE OF VARCHAR2(4000);
/

CREATE OR REPLACE FUNCTION split_String(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2_TABLE DETERMINISTIC
AS
  p_result       VARCHAR2_TABLE := VARCHAR2_TABLE();
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_result.EXTEND;
      p_result( p_result.COUNT ) := SUBSTR( i_str, p_start, p_end - p_start );
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_result.EXTEND;
      p_result( p_result.COUNT ) := SUBSTR( i_str, p_start, c_len - p_start + 1 );
    END IF;
  END IF;
  RETURN p_result;
END;
/

Query:

SELECT CASE WHEN split_String( '2,1' ) SUBMULTISET OF split_String( '1,3,2,4' )
            THEN 'Matches'
            ELSE 'No match'
            END AS match
FROM  DUAL;

Output:

MATCH
-------
Matches

Answer 2

You can split each comma-separated list into individual elements, count how many items are in the second list, count how many are in both lists (via a join), and compare the counts:

with list1 (item) as (
  select regexp_substr('1,2,3,4', '[^,]+', 1, level)
  from dual
  connect by regexp_substr('1,2,3,4', '[^,]+', 1, level) is not null
),
list2 (item) as (
  select regexp_substr('2,1', '[^,]+', 1, level)
  from dual
  connect by regexp_substr('2,1', '[^,]+', 1, level) is not null
)
select count(list1.item), count(list2.item)
from list2
left join list1 on list1.item = list2.item;

                      COUNT(LIST1.ITEM)                       COUNT(LIST2.ITEM)
--------------------------------------- ---------------------------------------
                                      2                                       2

If the second list had, say, '2,1,5' then the counts would be 2 and 3; since they are different that indicates a mismatch.

If you wanted to just get a flag saying whether they matches you coudl do something like:

with ...
select case when count(list1.item) = count(list2.item) then 1 
  else 0 end as matched
from list2
left join list1 on list1.item = list2.item;

When the second string is '2,1' that gets 1; when it's '2,1,5' it gets 0.

If the lists might contain duplicates when you could count distinct items. This won't work if either string is empty though.

使用分隔符检查另一个varcharracle中是否存在varchar，而不是相同的顺序

2 个答案: