Question

我正在尝试执行以下简单查询：

SELECT "Documents", "Sentences"."sentence","Sentences"."VectorValue", 
ts_rank("Sentences"."VectorValue", plainto_tsquery('Video provides a powerful way to help you prove your point. ')) as sim
FROM "Documents", "Sentences"
Where sim > 0.5
And "Documents"."Id" = "Sentences"."DID"
LIMIT 10;

但我一直得到这个错误：列“sim”不存在

我试过这个并且它工作但看起来效率不高，执行需要5秒钟：

SELECT ...., .... , 
ts_rank("Sentences"."VectorValue", plainto_tsquery('Video provides a powerful way to help you prove your point. '))
FROM "Documents", "Sentences"
Where ts_rank("Sentences"."VectorValue", plainto_tsquery('Video provides a powerful way to help you prove your point. ')) > 0.5
And "Documents"."Id" = "Sentences"."DID"
LIMIT 10;

通常，ts_rank会根据相关文档对特定查询的结果给出0-0.99的结果！

任何想法？

另外，这可以改进吗？

Answer 1

尝试此查询：

select
exe.*
from
(
    SELECT "Documents", "Sentences"."sentence","Sentences"."VectorValue", 
    ts_rank("Sentences"."VectorValue", plainto_tsquery('Video provides a powerful way to help you prove your point. ')) as sim
    FROM "Documents", "Sentences"
    And "Documents"."Id" = "Sentences"."DID"
) exe
where sim > 0.5
LIMIT 10;

Answer 2

将您的ts_rank写为横向连接：

SELECT "Documents", "Sentences"."sentence","Sentences"."VectorValue"
FROM "Documents", "Sentences",
ts_rank("Sentences"."VectorValue", plainto_tsquery('Video provides a powerful way to help you prove your point. ')) as sim
Where sim > 0.5
And "Documents"."Id" = "Sentences"."DID"
LIMIT 10;

关于ts_rank的PostgreSQL WHERE子句错误

2 个答案: