如何在WHERE子句中执行区分大小写的搜索（I&#39；M使用SQL Server）？

Can be done via changing the Collation. By default it is case insensitive.

Excerpt from the link:

SELECT 1
FROM dbo.Customers
WHERE   CustID = @CustID COLLATE SQL_Latin1_General_CP1_CS_AS
AND CustPassword = @CustPassword COLLATE SQL_Latin1_General_CP1_CS_AS

Or, change the columns to be case sensitive.

By using collation or casting to binary, like this:

SELECT *
FROM Users
WHERE
Username = @Username COLLATE SQL_Latin1_General_CP1_CS_AS
AND Password = @Password COLLATE SQL_Latin1_General_CP1_CS_AS
AND Username = @Username
AND Password = @Password

The duplication of username/password exists to give the engine the possibility of using indexes. The collation above is a Case Sensitive collation, change to the one you need if necessary.

The second, casting to binary, could be done like this:

SELECT *
FROM Users
WHERE
CAST(Username as varbinary(100)) = CAST(@Username as varbinary))
AND CAST(Password as varbinary(100)) = CAST(@Password as varbinary(100))
AND Username = @Username
AND Password = @Password

You can make the query using convert to varbinary – it’s very easy. Example:

Select * from your_table where convert(varbinary, your_column) = convert(varbinary, 'aBcD')

USE BINARY_CHECKSUM

SELECT
FROM Users
WHERE
BINARY_CHECKSUM(Username) = BINARY_CHECKSUM(@Username)
AND BINARY_CHECKSUM(Password) = BINARY_CHECKSUM(@Password)

use HASHBYTES

declare @first_value nvarchar(1) = 'a'
declare @second_value navarchar(1) = 'A'


if HASHBYTES('SHA1',@first_value) = HASHBYTES('SHA1',@second_value) begin
print 'equal'
end else begin
print 'not equal'
end


-- output:
-- not equal

...in where clause

declare @example table (ValueA nvarchar(1), ValueB nvarchar(1))


insert into @example (ValueA, ValueB)
values  ('a', 'A'),
('a', 'a'),
('a', 'b')


select  ValueA + ' = ' + ValueB
from    @example
where   hashbytes('SHA1', ValueA) = hashbytes('SHA1', ValueB)


-- output:
-- a = a


select  ValueA + ' <> ' + ValueB
from    @example
where   hashbytes('SHA1', ValueA) <> hashbytes('SHA1', ValueB)


-- output:
-- a <> A
-- a <> b

or to find a value

declare @value_b nvarchar(1) = 'A'


select  ValueB + ' = ' + @value_b
from    @example
where   hashbytes('SHA1', ValueB) = hasbytes('SHA1', @value_b)


-- output:
-- A = A

In MySQL if You don't want to change the collation and want to perform case sensitive search then just use binary keyword like this:

SELECT * FROM table_name WHERE binary username=@search_parameter and binary password=@search_parameter

use Latin1_General_CS as your collation in your sql db

Just as others said, you can perform a case sensitive search. Or just change the collation format of a specified column as me. For the User/Password columns in my database I change them to collation through the following command:

ALTER TABLE `UserAuthentication` CHANGE `Password` `Password` VARCHAR(255) CHARACTER SET latin1 COLLATE latin1_general_cs NOT NULL;

select * from incidentsnew1
where BINARY_CHECKSUM(CloseBy) = BINARY_CHECKSUM(Upper(CloseBy))

You can do by simply altering column collation as

Alter Table UserMaster
Alter Column Password varchar(50) COLLATE SQL_Latin1_General_CP1_CS_AS

If you are interested in Entity Framework approarch:

var customers = context.Customers
.Where(c => EF.Functions.Collate(c.Name, "SQL_Latin1_General_CP1_CS_AS") == "John")
.ToList();

See: https://learn.microsoft.com/en-us/ef/core/miscellaneous/collations-and-case-sensitivity#explicit-collation-in-a-query