Question

我有一个SQL查询，它只是在每个字段中返回NULL值。它返回数据库中输入的数据量的正确行数，但每个列值显示为NULL而不是MySQL中字段的值。

有人可以为我提出任何建议吗？

SELECT items.form_id as 'Form ID',
MAX(IF('field_id' LIKE 88,meta_value,NULL)) AS 'User ID',
MAX(IF('field_id' LIKE 96,meta_value,NULL)) AS 'Display Name',
MAX(IF('field_id' LIKE 95,meta_value,NULL)) AS 'User Role',
MAX(IF('field_id' LIKE 301,meta_value,NULL)) AS 'Your District',
MAX(IF('field_id' LIKE 97,meta_value,NULL)) AS 'Time Duty Logged',
MAX(IF('field_id' LIKE 84,meta_value,NULL)) AS 'Date of Duty',
MAX(IF('field_id' LIKE 85,meta_value,NULL)) AS 'Duty Start Time',
MAX(IF('field_id' LIKE 86,meta_value,NULL)) AS 'Duty End Time',
MAX(IF('field_id' LIKE 139,meta_value,NULL)) AS 'Duty Status',
MAX(IF('field_id' LIKE 142,meta_value,NULL)) AS 'Duty Type',
MAX(IF('field_id' LIKE 174,meta_value,NULL)) AS 'Which Event?',
MAX(IF('field_id' LIKE 103,meta_value,NULL)) AS 'Total Hours',
MAX(IF('field_id' LIKE 135,meta_value,NULL)) AS 'Duty Details',
MAX(IF('field_id' LIKE 136,meta_value,NULL)) AS 'End Section',
MAX(IF('field_id' LIKE 227,meta_value,NULL)) AS 'User Details',
MAX(IF('field_id' LIKE 228,meta_value,NULL)) AS 'End Section'
FROM wp_frm_item_metas as meta
JOIN wp_frm_items as items  ON (items.id = meta.item_id)
WHERE items.form_id LIKE 6
GROUP BY meta.item_id

我现在也尝试了以下内容，我仍然使用NULL代替每个字段值

SELECT items.form_id as 'Form ID',
MAX(IF('field_id' = 88,meta_value,NULL)) AS 'User_ID',
MAX(IF('field_id' = 96,meta_value,NULL)) AS 'Display_Name',
MAX(IF('field_id' = 95,meta_value,NULL)) AS 'User_Role',
MAX(IF('field_id' = 301,meta_value,NULL)) AS 'Your_District',
MAX(IF('field_id' = 97,meta_value,NULL)) AS 'Time_Duty_Logged',
MAX(IF('field_id' = 84,meta_value,NULL)) AS 'Date_of_Duty',
MAX(IF('field_id' = 85,meta_value,NULL)) AS 'Duty_Start_Time',
MAX(IF('field_id' = 86,meta_value,NULL)) AS 'Duty_End_Time',
MAX(IF('field_id' = 139,meta_value,NULL)) AS 'Duty_Status',
MAX(IF('field_id' = 142,meta_value,NULL)) AS 'Duty_Type',
MAX(IF('field_id' = 174,meta_value,NULL)) AS 'Which_Event?',
MAX(IF('field_id' = 103,meta_value,NULL)) AS 'Total_Hours',
MAX(IF('field_id' = 135,meta_value,NULL)) AS 'Duty_Details',
MAX(IF('field_id' = 136,meta_value,NULL)) AS 'End_Section',
MAX(IF('field_id' = 227,meta_value,NULL)) AS 'User_Details',
MAX(IF('field_id' = 228,meta_value,NULL)) AS 'End_Section'
FROM wp_frm_item_metas as meta
JOIN wp_frm_items as items  ON (items.id = meta.item_id)
WHERE items.form_id = 6
GROUP BY meta.item_id

Answer 1

两件事：您不必引用field_id列名称，并且您可能不想在数值上使用LIKE。

SELECT items.form_id as 'Form ID',
MAX(IF(field_id = 88,meta_value,NULL)) AS 'User_ID',
MAX(IF(field_id = 96,meta_value,NULL)) AS 'Display_Name',
MAX(IF(field_id = 95,meta_value,NULL)) AS 'User_Role',
MAX(IF(field_id = 301,meta_value,NULL)) AS 'Your_District',
MAX(IF(field_id = 97,meta_value,NULL)) AS 'Time_Duty_Logged',
MAX(IF(field_id = 84,meta_value,NULL)) AS 'Date_of_Duty',
MAX(IF(field_id = 85,meta_value,NULL)) AS 'Duty_Start_Time',
MAX(IF(field_id = 86,meta_value,NULL)) AS 'Duty_End_Time',
MAX(IF(field_id = 139,meta_value,NULL)) AS 'Duty_Status',
MAX(IF(field_id = 142,meta_value,NULL)) AS 'Duty_Type',
MAX(IF(field_id = 174,meta_value,NULL)) AS 'Which_Event?',
MAX(IF(field_id = 103,meta_value,NULL)) AS 'Total_Hours',
MAX(IF(field_id = 135,meta_value,NULL)) AS 'Duty_Details',
MAX(IF(field_id = 136,meta_value,NULL)) AS 'End_Section',
MAX(IF(field_id = 227,meta_value,NULL)) AS 'User_Details',
MAX(IF(field_id = 228,meta_value,NULL)) AS 'End_Section'
FROM wp_frm_item_metas as meta
JOIN wp_frm_items as items  ON (items.id = meta.item_id)
WHERE items.form_id = 6
GROUP BY meta.item_id

Answer 2

SELECT items.form_id as `Form ID`,
MAX(IF(`field_id` = 88,meta_value,NULL)) AS `User ID`,
MAX(IF(`field_id` = 96,meta_value,NULL)) AS `Display Name`,
MAX(IF(`field_id` = 95,meta_value,NULL)) AS `User Role`,
MAX(IF(`field_id` = 301,meta_value,NULL)) AS `Your District`,
MAX(IF(`field_id` = 97,meta_value,NULL)) AS `Time Duty Logged`,
MAX(IF(`field_id` = 84,meta_value,NULL)) AS `Date of Duty`,
MAX(IF(`field_id` = 85,meta_value,NULL)) AS `Duty Start Time`,
MAX(IF(`field_id` = 86,meta_value,NULL)) AS `Duty End Time`,
MAX(IF(`field_id` = 139,meta_value,NULL)) AS `Duty Status`,
MAX(IF(`field_id` = 142,meta_value,NULL)) AS `Duty Type`,
MAX(IF(`field_id` = 174,meta_value,NULL)) AS `Which Event?`,
MAX(IF(`field_id` = 103,meta_value,NULL)) AS `Total Hours`,
MAX(IF(`field_id` = 135,meta_value,NULL)) AS `Duty Details`,
MAX(IF(`field_id` = 136,meta_value,NULL)) AS `End Section`,
MAX(IF(`field_id` = 227,meta_value,NULL)) AS `User Details`,
MAX(IF(`field_id` = 228,meta_value,NULL)) AS `End Section`
FROM wp_frm_item_metas as meta
JOIN wp_frm_items as items  ON (items.id = meta.item_id)
WHERE items.form_id = 6
GROUP BY meta.item_id

感谢大家的建议 - 这完全解决了我。

SQL Query将每个值返回为NULL

2 个答案: