我无法将 data_type 从 TINYTEXT 更改为 DATE&/DATETIME

Question

I'm using SQL 8.0 and still learning , and I did some good changes on it. Now i'm stuck by the date, they are in the data_type of TINYTEXT from the import and each of the other field are VARCHAR(60) or INT for the Primary Key and I did pretty good job on it but i'm stuck for the data_type of the date.

I did this since the first day: it worked for date type

SELECT *, DATE_FORMAT(column_name , "%d/%m/%Y %H:%i:%s")
FROM table_name; 

(For a Datetime It didn't work.)

now I tried this:

INSERT INTO database_test.table_test.field_name(today) 
VALUES(STR_TO_DATE('07-25-2012','%m-%d-%y') ) 

Instead of %m-%d%y , I need this European format: %d/%m/%Y for DATE. And %d/%m/%Y %H:%i:%s for my DATETIME . Both are in TINYTEXT . (NB:they are date from 1899 to 2099 for the future "DATE" data_type.)

Answer 1

I'm going to make a couple of assumptions...

1. by SQL 8.0 you mean MySQL 8.0 ( STR_TO_DATE is non-standard so may not work with other database servers)
2. dates in your TINYTEXT field are stored in the format %d/%m/%Y %H:%i:%s

... and for the sake of argument I'm going to say the TINYTEXT date field is called date_string .

What I'd do is create a new DATE column and then UPDATE it with the value from date_string - using the STR_TO_DATE function (like you tried) - and if that's successful remove the original column and, possibly, rename the new DATE column.

---

Add the real date column

I'm calling it date_date here.

ALTER TABLE `table_test` ADD `date_date` DATE NOT NULL AFTER `date_string`;

UPDATE the real date with the value from the TINYTEXT field

(assuming d/m/YH:i:s format)

UPDATE `table_test` SET `date_date` = STR_TO_DATE(`date_string`, '%d/%m/%Y %H:%i:%s');

That should work as long as the format in your TINYTEXT column matches the format set in the STR_TO_DATE function. You'll have the original and converted dates in the table for now anyway, so you can check that the data looks OK.