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使用Union All的视图中的MySQL Case语句

union-all sql-view case sql mysql

AlIon · 技术社区 · 7 年前

我想在视图“v\u file\u details”中添加一个“Status”列,根据“v\u file\u details.records\u waiting\u count”和“v\u file\u details.records\u correct\u count”列中的数据,该列将有一个值。但我不明白如何在视图中使用Case?

create view v_file_details as
select 
fi.file_importer_id,
fi.file_name,
convert(time(0), fi.file_date) import_time,
fi.error_type,
((SELECT COUNT(*) From reservation Where file_importer_id = fi.file_importer_id AND status in ('S', 'S1')) + 
(SELECT COUNT(*) From error_file_record Where file_importer_id = fi.file_importer_id) +
(SELECT COUNT(*) From startup Where file_importer_id = fi.file_importer_id AND status in ('T', '6'))) as records_correct_count,
((SELECT COUNT(*) From location Where file_importer_id = fi.file_importer_id AND status = 'Y') + 
(SELECT COUNT(*) From reservation Where file_importer_id = fi.file_importer_id AND status = 'N') + 
(SELECT COUNT(*) From startup Where file_importer_id = fi.file_importer_id AND status in ('X', 'X1'))) as records_waiting_count,
case 'status' when records_waiting_count > 0 THEN 'Waiting' ELSE 'ACCEPTED', -- it is the problem, I don't know how to use CASE here
fi.new_file_name,

from file_importer fi
left join startup ts on fi.file_importer_id = ts.file_importer_id 
where ts.file_importer_id is not null

union all

select 
fi.file_importer_id,
fi.file_name,
convert(time(0), fi.file_date) import_time,
fi.error_type,
((SELECT COUNT(*) From reservation Where file_importer_id = fi.file_importer_id AND status in ('S', 'S1')) + 
(SELECT COUNT(*) From error_file_record Where file_importer_id = fi.file_importer_id) +
(SELECT COUNT(*) From startup Where file_importer_id = fi.file_importer_id AND status in ('T', '6'))) as records_correct_count,
((SELECT COUNT(*) From location Where file_importer_id = fi.file_importer_id AND status = 'Y') + 
(SELECT COUNT(*) From reservation Where file_importer_id = fi.file_importer_id AND status = 'N') + 
(SELECT COUNT(*) From startup Where file_importer_id = fi.file_importer_id AND status in ('X', 'X1'))) as records_waiting_count,
case 'status' when records_waiting_count > 0 THEN 'Waiting' ELSE 'ACCEPTED', --here the same
fi.new_file_name,

from file_importer fi
left join reservation res on fi.file_importer_id = res.file_importer_id 
where res.file_importer_id is not null

GO

1 回复 | 直到 7 年前

Nick SamSmith1986 7 年前

不能在中使用别名 SELECT records_waiting_count ,则需要使用它所引用的表达式。另外,您已经有一个名为 status CASE waiting_status 相反)。所以你的 案例 表达式应如下所示:

CASE WHEN ((SELECT COUNT(*) From location Where file_importer_id = fi.file_importer_id AND status = 'Y') + 
(SELECT COUNT(*) From reservation Where file_importer_id = fi.file_importer_id AND status = 'N') + 
(SELECT COUNT(*) From startup Where file_importer_id = fi.file_importer_id AND status in ('X', 'X1'))) > 0 THEN 'Waiting' ELSE 'Accepted' END AS waiting_status