Question

我已经尝试了各种解决方案，但它仍然给出了下面显示的错误 - 我没有想法（我也尝试更换“。$ _ SESSION ['plz']。” - 一个简单的数字部分，但没有改变任何东西：

$profilequery = "SELECT teacher.teacher_id, teacher.plz, teacher.ort,  
teacher.teacherprename, teacher.teachername, hours_week.hours_week, teacher.day_times, 
teacher.grade, teacher.study, teacher.references, teacher_subjects.qualification, 
teacher_subjects.subjectgrade, teacher_subjects.subjectqualification, 
ABS (teacher.plz - ".$_SESSION['plz'].") AS distance FROM (
(
SELECT teacher.teacher_id, teacher.plz, teacher.ort,  
teacher.teacherprename, teacher.teachername, hours_week.hours_week, teacher.day_times, 
teacher.grade, teacher.study, teacher.references, teacher_subjects.qualification, 
teacher_subjects.subjectgrade, teacher_subjects.subjectqualification FROM teacher LEFT JOIN
teacher_subjects
ON
teacher.teacher_id = teacher_subjects.teacher_id
LEFT JOIN
hours_week
ON
teacher.hours_id = hours_week.hours_id WHERE teacher.plz >= '".$_SESSION['plz']."' 
AND teacher_subjects.status_id = '1' ORDER BY teacher.plz LIMIT 10
) UNION ALL (
SELECT teacher.teacher_id, teacher.plz, teacher.ort,  
teacher.teacherprename, teacher.teachername, hours_week.hours_week, teacher.day_times, 
teacher.grade, teacher.study, teacher.references, teacher_subjects.qualification, 
teacher_subjects.subjectgrade, teacher_subjects.subjectqualification FROM teacher LEFT JOIN
teacher_subjects
ON
teacher.teacher_id = teacher_subjects.teacher_id
LEFT JOIN
hours_week
ON
teacher.hours_id = hours_week.hours_id WHERE teacher.plz >= '".$_SESSION['plz']."' 
AND teacher_subjects.status_id = '1' ORDER BY teacher.plz LIMIT 10
)
) AS a
ORDER BY distance
LIMIT 10";

它把它扔向我：

找不到列：1054在“字段列表”中的未知列'plz'在..
中

我真的没有看到任何错误，是否有人知道可能导致问题的原因？我感谢任何帮助！

编辑：删除了“老师”。和“teacher_subjects。”部分在查询中（也尝试仅在主查询或子查询中删除它）：

$profilequery = "SELECT teacher_id, plz, ort,  
teacherprename, teachername, hours_week, day_times, 
grade, study, references, qualification, 
subjectgrade, .subjectqualification, 
ABS (teacher.plz - ".$_SESSION['plz'].") AS distance FROM (
(
SELECT teacher_id, plz, ort,  
teacherprename, teachername, hours_week, day_times, 
grade, study, references, qualification, 
subjectgrade, .subjectqualification FROM teacher LEFT JOIN
teacher_subjects
ON
teacher.teacher_id = teacher_subjects.teacher_id
LEFT JOIN
hours_week
ON
teacher.hours_id = hours_week.hours_id WHERE teacher.plz >= '".$_SESSION['plz']."' 
AND teacher_subjects.status_id = '1' ORDER BY teacher.plz LIMIT 10
) UNION ALL (
SELECT teacher_id, plz, ort,  
teacherprename, teachername, hours_week, day_times, 
grade, study, references, qualification, 
subjectgrade, .subjectqualification FROM teacher LEFT JOIN
teacher_subjects
ON
teacher.teacher_id = teacher_subjects.teacher_id
LEFT JOIN
hours_week
ON
teacher.hours_id = hours_week.hours_id WHERE teacher.plz >= '".$_SESSION['plz']."' 
AND teacher_subjects.status_id = '1' ORDER BY teacher.plz LIMIT 10
)
) AS a
ORDER BY distance
LIMIT 10";

它抛出了这个：

完整性约束违规：1052字段列表中的'lehrer_id'列不明确'

现在我想这与LEFT JOIN部分有关（在使用此部分之前，只选择了plz和lehrer_id。我还尝试了LEFT JOIN部分在最后（在ALL UNION部分之后）但它仍然会抛出错误。

编辑2：解决了！ - ＆GT;必须提供查询以及LEFT JOIN的唯一名称（as b等），然后正确引用它们 - ＆gt;

$profilequery = "SELECT n.teacher_id, n.plz, n.ort,  
n.teacherprename, n.teachername, n.hours_week, n.day_times, 
n.grade, n.study, n.qualification, 
n.subjectgrade, n.subjectqualification, 
ABS (n.plz - ".$_SESSION['plz'].") AS distance FROM (
(
SELECT b.teacher_id, b.plz, b.ort,  
b.teacherprename, b.teachername, sw.hours_week, b.day_times, 
b.grade, b.study lf.qualification, 
lf.subjectgrade, lf.subjectqualification FROM teacher as b LEFT JOIN
teacher_subjects as lf
ON
teacher.teacher_id = teacher_subjects.teacher_id
LEFT JOIN
hours_week as sw
ON
b.hours_id = sw.hours_id WHERE b.plz >= '".$_SESSION['plz']."' 
AND lf.status_id = '1' ORDER BY b.plz LIMIT 10
) UNION ALL (
SELECT b.teacher_id, b.plz, b.ort,  
b.teacherprename, b.teachername, sw.hours_week, b.day_times, 
b.grade, b.study lf.qualification, 
lf.subjectgrade, lf.subjectqualification FROM teacher as b LEFT JOIN
teacher_subjects as lf
ON
teacher.teacher_id = teacher_subjects.teacher_id
LEFT JOIN
hours_week as sw
ON
b.hours_id = sw.hours_id WHERE b.plz >= '".$_SESSION['plz']."' 
AND lf.status_id = '1' ORDER BY b.plz LIMIT 10
)
) AS n
ORDER BY distance
LIMIT 10";

Answer 1

您的子查询必须附加plz列，否则将无法在主查询中看到，因此：

$profilequery = "SELECT teacher_id, ABS (plz - ".$_SESSION['plz'].") AS distance FROM (
(
SELECT teacher_id, plz FROM teacher WHERE plz >= '".$_SESSION['plz']."' ORDER BY teacher.plz LIMIT 10
) UNION ALL (
SELECT teacher_id, plz FROM teacher WHERE plz >= '".$_SESSION['plz']."' ORDER BY plz DESC
LIMIT 10
)
) AS a
ORDER BY distance
LIMIT 10";

Answer 2

见上面的更新文章（编辑2） - ＆gt;必须提供查询以及LEFT JOIN的唯一名称（如b等），然后正确引用它们

字段列表中的未知列（PHP + MySQL / PDO）

2 个答案: