SQL Working With Dates

The most difficult part when working with dates is to be sure that the format of the date you are trying to insert, matches the format of the date column in the database.

As long as your data contains only the date portion, your queries will work as expected. However, if a time portion is involved, it gets more complicated.

SQL Date Data Types

MySQL comes with the following data types for storing a date or a date/time value in the database:

DATE - format YYYY-MM-DD
DATETIME - format: YYYY-MM-DD HH:MI:SS
TIMESTAMP - format: YYYY-MM-DD HH:MI:SS
YEAR - format YYYY or YY

SQL Server comes with the following data types for storing a date or a date/time value in the database:

DATE - format YYYY-MM-DD
DATETIME - format: YYYY-MM-DD HH:MI:SS
SMALLDATETIME - format: YYYY-MM-DD HH:MI:SS
TIMESTAMP - format: a unique number

Note: The date types are chosen for a column when you create a new table in your database!

SQL Working with Dates

Look at the Product table:

date product table

Now we want to select the records with an Order_date of "2023-05-17" from the table above.

We use the following SELECT statement:

Example

SELECT * FROM 
 products WHERE Order_date = '2023-05-17';

Note : Two dates can easily be compared if there is no time component involved!

Now, assume that the "Orders" table looks like this (notice the added time-component in the "OrderDate" column):

date table

If we use the same SELECT statement as above:

Example

SELECT * FROM 
products WHERE Order_date = '2023-05-17';

we will get no result! This is because the query is looking only for dates with no time portion.