UPDATE with ORDER BY and LIMIT not working in MYSQL - mysql

Question

I am new to MYSQL, and unable to resolve or even with so many answers on this forum, unable to identiy the error in this statement. I am using MYSQL database.
I have 2 tables: Ratemaster and rates, in which a customer can have 1 product with different rates.
Because of this, there is a duplication of customer and product fields, only the rate field changes.
Now Table Ratemaster has all the fields : id, Customer code, Product, Rate, user
whereas Table Rates has only: id, cust code, Rate, user.
- user field is for checking session_user.
Now Table Ratemaster has 3 records with all field values being same except Rate field empty.
Table Rates has different rates.
I want to have all rates to be updated in Ratemaster from Rates table. I am unable to do this with UPDATE and LIMIT mysql command, it is giving error as:
Incorrect usage of UPDATE and LIMIT
UPDATE Ratemaster, Rates
SET Ratemaster.Rate=Rates.Rate
WHERE Ratemaster.user=Rates.user
LIMIT 1

Answer 1

Usually you can use LIMIT and ORDER in your UPDATE statements, but in your case not, as written in the MySQL Documentation 12.2.10. UPDATE Syntax:
For the multiple-table syntax, UPDATE updates rows in each table named
in table_references that satisfy the conditions. In this case, ORDER
BY and LIMIT cannot be used.
Try the following:
UPDATE Ratemaster
SET Ratemaster.Rate =
(
SELECT Rates.Rate
FROM Rates
WHERE Ratemaster.user = Rates.user
ORDER BY Rates.id
LIMIT 1
)

Answer 2

Salam
You can use this method and work properly !
UPDATE Ratemaster, Rates
SET Ratemaster.Rate=Rates.Rate
WHERE Ratemaster.user=Rates.user
ORDER BY Rates.id
LIMIT 1

Answer 3

Work It 100%
UPDATE table SET Sing='p' ORDER BY sr_no LIMIT 10;

Answer 4

Read article about
How to use ORDER BY and LIMIT on multi-table updates in MySQL
For the multiple-table syntax, UPDATE updates rows in each table named
in table_references that satisfy the conditions. In this case, ORDER
BY and LIMIT cannot be used.

Answer 5

The problem is that LIMIT is only to be used with SELECT statements, as it limits the number of rows returned by the query.
From: http://dev.mysql.com/doc/refman/5.5/en/select.html
The LIMIT clause can be used to constrain the number of rows returned by
the SELECT statement. LIMIT takes one or two numeric arguments, which
must both be nonnegative integer constants, with these exceptions:
Within prepared statements, LIMIT parameters can be specified using ? placeholder markers.
Within stored programs, LIMIT parameters can be specified using integer-valued routine parameters or local variables as of MySQL 5.5.6.
With two arguments, the first argument specifies the offset of the
first row to return, and the second specifies the maximum number of
rows to return. The offset of the initial row is 0 (not 1):
SELECT * FROM tbl LIMIT 5,10; # Retrieve rows 6-15
To retrieve all rows from a certain offset up to the end of the result
set, you can use some large number for the second parameter. This
statement retrieves all rows from the 96th row to the last:
SELECT * FROM tbl LIMIT 95,18446744073709551615;
With one argument, the value specifies the number of rows to return
from the beginning of the result set:
SELECT * FROM tbl LIMIT 5; # Retrieve first 5 rows
In other words, LIMIT row_count is equivalent to LIMIT 0, row_count.
For prepared statements, you can use placeholders. The following
statements will return one row from the tbl table:
SET #a=1; PREPARE STMT FROM 'SELECT * FROM tbl LIMIT ?'; EXECUTE STMT
USING #a;
The following statements will return the second to sixth row from the
tbl table:
SET #skip=1; SET #numrows=5; PREPARE STMT FROM 'SELECT * FROM tbl
LIMIT ?, ?'; EXECUTE STMT USING #skip, #numrows;
For compatibility with PostgreSQL, MySQL also supports the LIMIT
row_count OFFSET offset syntax.
If LIMIT occurs within a subquery and also is applied in the outer
query, the outermost LIMIT takes precedence. For example, the
following statement produces two rows, not one:
(SELECT ... LIMIT 1) LIMIT 2;