PostgreSQL：从列值向时间戳添加间隔
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PostgreSQL: Add Interval to Timestamp from column value
提问by NakaBr
I need to add minutes coming from an integer column with a timestamp to compare to another column.
我需要添加来自带有时间戳的整数列的分钟以与另一列进行比较。
Here's an example:
下面是一个例子：
SELECT t1.id_liame, t1.id_table, t1.periodicidade , t3.data_extracao,
CASE WHEN(NOW() < (e.data_extracao + INTERVAL t1.periodicidade || '
MINUTES'))
THEN 'yes' ELSE 'no' END
FROM table1 as t1 LEFT JOIN liame_has_extracao as t2 USING(id_liame)
LEFT JOIN extracao as t3 USING(id_extracao)
l.periodicidadeis integer (minutes)
I need to verify if data_extracao(timestamp)is greater then NOW() + l.periodicidade(integer - minutes).
l.periodicidade是整数（分钟）
我需要验证是否data_extracao(timestamp)大于 then NOW() + l.periodicidade(integer - minutes)。
How can i do it?
我该怎么做？
回答by Frank Bollack
You can write your query like this:
您可以像这样编写查询：
SELECT
t1.id_liame,
t1.id_table,
t1.periodicidade,
t3.data_extracao,
CASE
WHEN(NOW() < (t3.data_extracao + (INTERVAL '1 min' * t1.periodicidade)))
THEN 'yes' ELSE 'no'
END
FROM table1 AS t1
LEFT JOIN liame_has_extracao AS t2 USING(id_liame)
LEFT JOIN extracao AS t3 USING(id_extracao)
As you can see, you can multiply intervals with integers so with INTERVAL '1 minute'you define your base unit and multiply your actual time interval.
如您所见，您可以将间隔与整数相乘，以便INTERVAL '1 minute'定义基本单位并乘以实际时间间隔。
Hope that helps
希望有帮助
