什么 T-SQL 查询会检索 Email 列的所有值，其中 First_Name 和 Last_ Name 列的值位于 Email 列中？

Question

There's a table with 3 columns, 'First_Name', 'Last_Name', 'Email'. Some values in Email column contain First_Name and Last_Name column values concatenated together. Ie, Email = 'JohnSmith22@example.com' where First_Name = 'John', Last_Name = 'Smith'.

Other Email values for some rows are unrelated. Ie First_Name = 'Steven', Last_Name = 'Paul', Email = 'random12345@example2.com'. What query would retrieve only values of Email column, where First_Name and Last_Name are in the column?

Answer 1

You can check if the email starts with the concatenation of the first and last names, using like :

select t.*
from mytable t
where email like first_name + last_name + '%'

Answer 2

In case of the name field have a heterogeneous character case , you need to convert it to lower and check. The other thing is sometimes the order of First and Last name in the email might be different so you need to consider this case as well.

SELECT *
FROM theTable
WHERE lower(email) LIKE '%' + lower(name) + '%' + LOWER(lastname) + '%'
    OR lower(email) LIKE '%' + lower(lastname) + '%' + LOWER(name) + '%'

Answer 3

What query would retrieve only values of Email column, where First_Name and Last_Name are in the column?

If you want first and last name in the column -- but other characters as well -- I would suggest:

where email like '%' + first_name + '%@%' and
      email like '%' + last_name + '%@%'

This checks that the first and last names are before the @ , in any order -- and with any other characters.