Oracle SQL Migrate data from date range / period to months

Question

I have some problems in migrating data from one table to another. Im using a Oracle 11 database. In my problem, one table states some values which are valid in a specific date range (start date and end date). The other table, to which the data should be migrated to, should state these values per month (MMYYY). So for a specific time frame (for example 01/01/2010 to 31/12/2010), the data should be stated per month (01/2010, 02/2010, ..., 31/2010). I was trying to create a suitable sql insert statement for this case but i was not successful in it.

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Example:

Table 1 has the following attributes: ID (PK), START_DATE, END_DATE, VALUE

Table 2 has the following attributes: ID (PK), MONTH, YEAR, VALUE

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Table 1:

• ID = 1, START_DATE = 01/01/2010, END_DATE = 31/12/2015, VALUE = 5
• ID = 2, START_DATE = 01/01/2012, END_DATE = 31/12/2013, VALUE = 10
• ID = 3, START_DATE = 01/01/2018, END_DATE = 31/12/2020, VALUE = 15

These entries should look like the following in the new table:

Table 2:

• ID = 1, MONTH = 01, YEAR = 2010, VALUE = 5
• ID = 1, MONTH = 02, YEAR = 2010, VALUE = 5
• ID = 1, MONTH = 03, YEAR = 2010, VALUE = 5
• ...
• ID = 1, MONTH = 12, YEAR = 2015, VALUE = 5
• ID = 2, MONTH = 01, YEAR = 2012, VALUE = 10
• ID = 2, MONTH = 02, YEAR = 2012, VALUE = 10
• ID = 2, MONTH = 03, YEAR = 2012, VALUE = 10
• ...
• ID = 2, MONTH = 12, YEAR = 2013, VALUE = 10
• ID = 3, MONTH = 01, YEAR = 2018, VALUE = 15
• ID = 3, MONTH = 02, YEAR = 2018, VALUE = 15
• ID = 3, MONTH = 03, YEAR = 2018, VALUE = 15
• ...
• ID = 3, MONTH = 12, YEAR = 2020, VALUE = 15

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Is there a best practice way to do this? Or does anyone have an idea? Thanks for any advice!

Answer 1

使用TO_DATE（'mm / yyyy'）转换字段，您可以在这里找到更多信息： https : //www.techonthenet.com/oracle/functions/to_date.php