如何搜索包含特定单词的行然后返回每个单词的计数？

Question

我有150,000行数据，我试图在Google BigQuery中查询。

列Text包含各种长度的文本，我想从中查询特定关键字。

我已经得到尽可能下面的查询返回包含特定关键字（比如Facebook）的所有行：如何提高查询

1）：

SELECT Text From Data.Set_1 
WHERE Text CONTAINS 'facebook' 

问题因此它会在新的列中的“文本”中返回所有关键字“脸谱”的总次数？ 2）如何将这个数据放大到多个关键字（Facebook，cnn，bbc，twitter）并返回数据中每个关键字的总数（例如facebook 42，cnn 54，bbc 88，twitter 49）？

Answer 1

为BigQuery的传统的SQL

SELECT 
    keyword, 
    COUNT(1) AS rows, 
    SUM(INTEGER((LENGTH(Text) - LENGTH(REPLACE(Text, keyword, '')))/LENGTH(keyword))) AS occurences 
FROM YourTable 
CROSS JOIN keywords 
WHERE Text CONTAINS keyword 
GROUP BY keyword 

实施例与

SELECT 
    keyword, 
    COUNT(1) AS rows, 
    SUM(INTEGER((LENGTH(Text) - LENGTH(REPLACE(Text, keyword, '')))/LENGTH(keyword))) AS occurences 
FROM (
    SELECT Text FROM 
    (SELECT 'facebookfacebookcnnbbccnn' AS Text), 
    (SELECT 'facebook' AS Text), 
    (SELECT 'cnn' AS Text) 
) AS words 
CROSS JOIN (
    SELECT keyword FROM 
    (SELECT 'facebook' AS keyword), 
    (SELECT 'cnn' AS keyword), 
    (SELECT 'bbc' AS keyword) 
) AS keywords 
WHERE Text CONTAINS keyword 
GROUP BY keyword 

对于大量查询标准SQL播放（见Enabling Standard SQL）

SELECT 
    keyword, 
    COUNT(1) AS `rows`, 
    SUM((LENGTH(Text) - LENGTH(REPLACE(Text, keyword, '')))/LENGTH(keyword)) AS occurences 
FROM YourTable 
JOIN keywords 
ON STRPOS(Text, keyword) > 0 
GROUP BY keyword 

实施例与

打

Answer 2

您可以使用派生表包括所有你正在寻找的话，然后用聚集计数比赛：

SELECT w.keyword, COUNT(s.Text) 
From (SELECT 'facebook' as keyword UNION ALL 
     SELECT 'cnn' 
    ) w LEFT JOIN 
    Data.Set_1 s 
    ON s.Text CONTAINS w.keyword 
GROUP BY w.keyword; 

请注意：这不是特别有效。性能应该与关键字数量大致呈线性关系。