mysql - 查询结果集为零时如何显示记录？

Question

我正在查询几个表以获取每个答案的计数，当在结果表中找到记录时，此查询工作正常。我想以一种方式处理此查询，以防万一在结果表中找不到任何答案或问题的记录，它必须显示该值的计数“0”及其各自的问题和答案。我必须在这个查询中做出什么改变？或者有什么办法让我知道吗？提前致谢。

这是我的查询。

SELECT s.NAME AS surveyname,
    COUNT(r.answer_id) AS totalAnswer,
    q.id AS questionid,
    q.question AS question,
    a.answer AS answer,
    COUNT(r.textbox) AS totalTextbox,
    COUNT(r.textboxmulti) AS totalTextboxmulti,
    qt.template AS template,
    s.NAME AS surveyname,
    COUNT(r.other) AS other
FROM surveys s
INNER JOIN survey_results AS sr
    ON s.id = sr.survey_id
INNER JOIN results AS r
    ON sr.id = r.surveyresults_id
INNER JOIN questions AS q
    ON r.question_id = q.id
INNER JOIN questiontypes AS qt
    ON q.questiontype_id = qt.id
LEFT JOIN answers AS a
    ON r.answer_id = a.id
WHERE s.id = < cfqueryparam cfsqltype = "cf_sql_integer" value = "#arguments.surveyid#" >
GROUP BY q.id,
    a.id
ORDER BY q.id, a.id a.rank

如果没有找到匹配的记录，它应该显示如下所示。

surveyname totalanswer qid question answer totaltextbox totaltextboxmulti template totalother
somename     0         1 what ?   yes     0              0              multiple  0
somename     0         1 what ?   no      0              0              multiple  0

如果有匹配的记录，那么它应该在 totalanswer 或 totaltextbox 等中显示计数。

Answer 1

尝试添加这个COUNT(ifnull(r.other,0)) AS other

    SELECT s.NAME AS surveyname,
    COUNT(r.answer_id) AS totalAnswer,
    q.id AS questionid,
    q.question AS question,
    a.answer AS answer,
    COUNT(r.textbox) AS totalTextbox,
    COUNT(r.textboxmulti) AS totalTextboxmulti,
    qt.template AS template,
    s.NAME AS surveyname,
    COUNT(ifnull(r.other,0)) AS other
FROM surveys s
INNER JOIN survey_results AS sr
    ON s.id = sr.survey_id
INNER JOIN results AS r
    ON sr.id = r.surveyresults_id
INNER JOIN questions AS q
    ON r.question_id = q.id
INNER JOIN questiontypes AS qt
    ON q.questiontype_id = qt.id
LEFT JOIN answers AS a
    ON r.answer_id = a.id
WHERE s.id = < cfqueryparam cfsqltype = "cf_sql_integer" value = "#arguments.surveyid#" >
GROUP BY q.id,
    a.id
ORDER BY a.rank

编辑

同样正如@SlowCoder 建议的那样，尝试LEFT JOIN在结果表上使用。