MySQL - WEIGHT_STRING() Function

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The MySQL WEIGHT_STRING() function returns the weight for the input string.

It accepts a non-binary string as input and returns the weight string for it, this string contains the collation weights. If the input string is a binary value, the result is the same as the input string. This is because the weight for each byte in a binary string is the byte value.

Syntax

Following is the syntax of MySQL WEIGHT_STRING() function −

WEIGHT_STRING(str [AS {CHAR|BINARY}(N)] [flags])

Parameters

This function takes a non-binary string value as a parameter.

Return Value

This function returns the weight of the given string.

Example

The following example returns the weight string for the input string 'tutorialspoint' using the specified collation ('utf8mb4_0900_ai_ci') −

SELECT WEIGHT_STRING(_utf8mb4 'tutorialspoint' COLLATE utf8mb4_0900_ai_ci);

The result is a binary string that represents the comparison and sorting value of the input string as shown below −

WEIGHT_STRING(_utf8mb4 'tutorialspoint' COLLATE utf8mb4_0900_ai_ci
0x1E951EB51E951DDD1E331D321C471D771E711E0C1DDD1D321DB91E95

If you disable the --binary-as-hex value, the result of the above query will be as follows. To display the non-printable values, you can use the HEX() function −

SELECT HEX(WEIGHT_STRING(_utf8mb4 'tutorialspoint' COLLATE utf8mb4_0900_ai_ci));

The result obtained is as follows −

HEX(WEIGHT_STRING(_utf8mb4 'tutorialspoint' COLLATE utf8mb4_0900_ai_ci))
1E951EB51E951DDD1E331D321C471D771E711E0C1DDD1D321DB91E95

Example

If you pass a binary string as an argument to this function it returns the same binary string −

SELECT WEIGHT_STRING(CAST('test' AS BINARY));

The output obtained is as follows −

WEIGHT_STRING(CAST('test' AS BINARY))
0x74657374

If you disable the --binary-as-hex value, the result of the above query will be as follows. To display the non-printable values, you can use the HEX() function −

SELECT WEIGHT_STRING(CAST('test' AS BINARY));

The result produced is as shown below −

WEIGHT_STRING(CAST('test' AS BINARY))
test

Example

You can also cast the string using CHAR or BINARY −

SET NAMES 'latin1';
SELECT HEX(WEIGHT_STRING('tutorialspoint' AS CHAR(4)));

The result produced is as follows −

HEX(WEIGHT_STRING('tutorialspoint' AS CHAR(4)))
5455544F

Example

If you pass NULL as an argument to this function it returns the same NULL −

SELECT WEIGHT_STRING(NULL);

Following is the output of the above code −

WEIGHT_STRING(NULL)
0x

If you disable the --binary-as-hex value, the result of the above query will be as follows. To display the non-printable values, you can use the HEX() function −

SELECT WEIGHT_STRING(NULL);

The result obtained is as shown below −

WEIGHT_STRING(NULL)
NULL