Expecting exact results when using contains clause in Oracle

问题

I have a below contains clause query to get the best match queries. I have below two values in the table:

1. TRUSTS ACT 1973 and 
2. TRUST ACCOUNTS ACT 1973.

When I am searching using the below query with the string "TRUST ACT 1973", for this search the actual result comes as TRUST ACCOUNTS ACT 1973. But I am expecting the exact result as *TRUSTS ACT 1973*.

Query:

SELECT
    /*+first_rows(11) index(a fuzzy_leg_nm_idx)*/
    a.unique_legislation_id,
    a.legislation_name,
    a.jurisdiction,
    score(1) sc
  FROM AU_LEG_PARALLEL_FUZZY a  
    WHERE contains (legislation_name, 
    '<query> 
        <textquery lang="ENGLISH" grammar="CONTEXT"> '
         || '<progression>
                <seq>{TRUST} ACCUM {ACT} ACCUM {1973}</seq>
            </progression>
        </textquery>
        <score datatype="INTEGER" algorithm="COUNT"/>
     </query>', 1) > 0
ORDER BY score(1) DESC;

回答1:

Both records match the ACCUM query. Assuming that you used the default BASIC_LEXER with no word stemming TRUST ACCOUNTS ACT 1973 scores higher mostly because TRUST matches exactly to your query. If you change the query to {TRUSTS} ACCUM {ACT} ACCUM {1973} then TRUSTS ACT 1973 would get a higher score.

Depending on your requirements, you might want to consider a phrase search rather than ACCUM, e.g. CONTAINS(title, '{TRUSTS} {ACT} {1973}') > 0. In this case, the phrase has to match exactly to a record.

来源：https://stackoverflow.com/questions/41295922/expecting-exact-results-when-using-contains-clause-in-oracle