Does Mysql have an equivalent to @@ROWCOUNT like in mssql?

How can I ge开发者_如何学Got row count values in MySQL as @@ROWCOUNT does in mssql?

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For SELECTs you can use the FOUND_ROWS construct (documented here):

SELECT SQL_CALC_FOUND_ROWS something FROM your_table WHERE whatever;
SELECT FOUND_ROWS( ) ;

which will return the number of rows in the last SELECT query (or if the first query has a LIMIT clause, it returns the number of rows there would've been without the LIMIT).

For UPDATE/DELETE/INSERT, it's the ROW_COUNT construct

INSERT INTO your_table VALUES (1,2,3);
SELECT ROW_COUNT();

which will return the number of affected rows.

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mysql> SELECT SQL_CALC_FOUND_ROWS * FROM tbl_name

    -> WHERE id > 100 LIMIT 10;

mysql> SELECT FOUND_ROWS();

Read more about this here

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The simplest way would be to use a variable:

mysql> SELECT @rowcount:=COUNT(*) FROM my_table;
mysql> SELECT @rowcount;

Or you can use FOUND_ROWS() construct after putting a SQL_CALC_FOUND_ROWS in a SELECT statement.

mysql> SELECT SQL_CALC_FOUND_ROWS * FROM my_table;
mysql> SELECT FOUND_ROWS();

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There is another way:

CREATE TEMPORARY TABLE `results` AS ( *** Your query without LIMIT *** );

Get the row count

SELECT COUNT(*) FROM `results`;

Get your subset

SELECT * FROM `results` LIMIT 5,10;

The temporary table exists only in the current session. I would still clean-up afterwards

DROP TEMPORARY TABLE `results`;

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Count the number of rows in a sub-query in the where clause. Then test if the total number of rows is greater than zero.

SELECT customerNumber, customerName, creditLimit FROM customers where (SELECT count(*) as tot FROM customers) > 0;