我尝试了下面的命令。它是DataSource的{{1}}，它写在我的GridView页面上，因此我无法使用.aspx或""等字符。这段代码不会给我任何回报。我还尝试传递（string.empty，“”和null）作为''中的参数。什么都行不通，我不知道还能做什么...
codebehind SelectCommand="SELECT ch.id, sit.descricao as situacao, resp.responsavel, ch.dt_cadastro, ch.previsao_termino, func.descricao as funcionalidade,
proj.descricao as projeto ,pr.id as prid, pr.prioridade, clb.clube
FROM chamados AS ch
INNER JOIN prioridades as pr ON ch.prioridade = pr.id
INNER JOIN clubes as clb ON ch.clube = clb.id
INNER JOIN responsaveis as resp ON ch.responsavel = resp.id
INNER JOIN situacoes as sit ON ch.situacao = sit.id
INNER JOIN projetos as proj ON ch.projeto = proj.id
INNER JOIN funcionalidades as func ON ch.funcionalidade = func.id WHERE ch.responsavel IS NULL"
我希望将Obs:字段过滤为null字段。
（我知道int32不能int32）但我只是不知道该怎么做，所以我尝试了所想到的一切。
答案 0 :(得分：0)
此查询将始终不返回任何结果，因为您在此语句中使用INNER JOIN：
INNER JOIN responsaveis as resp ON ch.responsavel = resp.id
并使用WHERE状态，将INNER JOIN个文件中的一个与NULL进行比较
WHERE ch.responsavel IS NULL
INNER JOIN加入 ONLY 字段，这些字段为NOT NULL。所以这两个声明除了彼此之外。
答案 1 :(得分：0)
我发现了问题，原因是：
我正在使用INNER JOINS，而@valex告诉我：
The INNER JOIN joins ONLY fields which are NOT NULL. So these two statement except each other.
解决方案是更改INNER JOIN的{{1}}并且像魅力一样工作！
谢谢大家！