检查表名是否包含日期

Question

I am trying to find out all tables whose name end with yyyy_mm_dd, eg temp_2017_10_01 , alpha_2016_11_02 .

Currently I am trying to do this:

SELECT table_name 
FROM information_Schema.tables
WHERE table_name LIKE '%2017_%'
OR table_name LIKE '%2016_%'
OR table_name LIKE '%2015_%'

What is an elegant way of doing this ?

Answer 1

You could try using regex like:

SELECT table_name 
FROM information_Schema.tables
WHERE table_name ~* '201[567]_.*'

This would look for years 2015, 2016, and 2017. If you wanted a more generic pattern to find any date you could use this:

SELECT table_name 
FROM information_Schema.tables
WHERE table_name ~* '[0-9]{4}_[0-9]{2}_[0-9]{2}'

Strictly speaking, the above pattern is now too generic, because it allows things like 9999_99_99 which are not valid dates. But my guess is this is good enough for your use case because you aren't trying to validate table names, just extract them.

Answer 2

TRY THIS : if following used all the functions are available in the respective database as it's working fine in SQL SERVER OR you can use equivalent function instead

SELECT table_name 
FROM information_Schema.tables
WHERE ISDATE(REPLACE(RIGHT(table_name, 10), '_', '-')) = 1

Answer 3

You can use something like this. using simple substr and to_date functions, will work every where.

SELECT table_name
FROM information_Schema.tables WHERE To_Date(SubStr(table_name,Length(table_name)-9,4)||'-'||SubStr(table_name,Length(table_name)-4,2)||'-'||SubStr(table_name,Length(table_name)-1,2),'YYYY-MM-DD') BETWEEN To_Date('01-JAN-2016') AND To_Date('31-DEC-2016');

will give you all the tables between 1st Jan 2016 and 31st Dec 2016 and you can just substitute whatever range you want. If you want all, then you can just give '01-JAN-1950' and '31-DEC-3000' to be sure you can get all of them ;)