如何根据时间戳删除mysql数据？

Question

I am using System.Data.SqlLite.dll lite version 1.0.105.0

I have a very simple MySQL database.

I create a single table in the Database using the following:

CREATE TABLE SessionInfo (session nvarchar(100), state nvarchar(25), ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP)

I (successfully) add data to the table:

INSERT INTO SessionInfo (session, state) VALUES ('test', '1')

When I try to purge data from the table using this statement:

DELETE FROM SessionInfo WHERE ts < ADDDATE( NOW(), INTERVAL -1 MINUTE )

(I have also tried the following)

DELETE FROM SessionInfo WHERE ts < CURRENT_TIMESTAMP - interval '1' minute
DELETE FROM SessionInfo WHERE ts < DATE_SUB(NOW(), INTERVAL 1 MINUTE)

In all cases, I get this error:

System.Data.SQLite.SQLiteException was unhandled
ErrorCode=1
HResult=-2147467259
Message=SQL logic error or missing database
near "MINUTE": syntax error
Source=System.Data.SQLite

When I try either of these:

DELETE FROM SessionInfo WHERE ts < NOW() - INTERVAL 1 MINUTE
DELETE FROM SessionInfo WHERE ts < NOW() - INTERVAL '1' MINUTE

I get this error:

System.Data.SQLite.SQLiteException was unhandled
ErrorCode=1
HResult=-2147467259
Message=SQL logic error or missing database
near "'1'": syntax error
Source=System.Data.SQLite

I tried wrapping timestamp in UNIX_TIMESTAMP macro...

DELETE FROM SessionInfo WHERE UNIX_TIMESTAMP(ts) < 
UNIX_TIMESTAMP(DATE_SUB(NOW(), INTERVAL 1 MINUTE))

Still same error:

System.Data.SQLite.SQLiteException was unhandled
ErrorCode=1
HResult=-2147467259
Message=SQL logic error or missing database
near "1": syntax error
Source=System.Data.SQLite

I tried deleting records in between timestamps:

DELETE FROM SessionInfo WHERE ts between now() - interval 1 hour and now()

I still get the same result:

System.Data.SQLite.SQLiteException was unhandled
ErrorCode=1
HResult=-2147467259
Message=SQL logic error or missing database
near "1": syntax error

So, I just tried this:

DELETE FROM SessionInfo WHERE ts < CURRENT_TIMESTAMP

and ALL of my records are deleted... so I know I can delete... just not the stuff I want to delete

Thanks to LSerni, here is my working code: ( note: I was using minutes for testing... but real code will be in days )

DELETE FROM SessionInfo WHERE ts < DATETIME('NOW', '-7 DAY')

Answer 1

You are using MySQL syntax, but SQLite does not support it. There is no NOW() function, nor there is a date adding function. You must use date modifiers .

Try:

 SELECT DATETIME('NOW', '-1 MINUTE');

or

 DELETE ... WHERE ts < DATETIME('NOW', '-1 MINUTE');