如何使用LIKE和通配符提高联接性能？

Question

我有一系列联接，这些联接使用运算符LIKE，CASE和通配符将通讯录与交易表合并。该查询的执行速度非常慢：1 m 4 s 244 ms并提取：677 ms。我将如何提高该查询的性能？

from contacts left join deals on deals.associated_vids like
                          Case
                              when canonical_vid = split_part(associated_vids, ',', 1)
                                  then concat(canonical_vid,'%')
                              when canonical_vid =
                                   split_part(associated_vids, ',', (CHAR_LENGTH(associated_vids) - CHAR_LENGTH(REPLACE(associated_vids, ',', ''))) / CHAR_LENGTH(',')+1)
                                  then concat('%',canonical_vid)
                              when canonical_vid is not null
                                  then concat('%,', concat(canonical_vid,',%')) End

我希望尽可能减少整个运行时间，最好少于一分钟。