Question

我想得到表中存在的行数。

+---+----+
|id |name|
+---+----+
|100|a   |
+---+----+
|201|b   |
+---+----+
|302|c   |
+---+----+
|403|d   |
+---+----+
|504|e   |
+---+----+

在上表中，我希望输出为4（即）该行的计数存在。我有'd'值并且必须编写查询以将输出设为4 其中name = d

我认为代码将类似于下面的内容，

select count(*) ......

Answer 1

SELECT ROW_NUMBER() OVER(ORDER BY id) FROM yourtable WHERE name='d'

MySQL版

SET @rank=0;
SELECT   @rank := @rank+1 AS rank
FROM     yourtable WHERE name='d'
ORDER BY id asc

Answer 2

获取行号

SELECT ROW_NUMBER() OVER(ORDER BY id) from table WHERE name='d'

要使用您的条件获取行数，请使用以下查询

select count(*) as count from table where name = 'b'

Answer 3

如果我正确理解你，那么这个问题就是你想要的：

set @row_number = 0; 
select @row_number := @row_number + 1 as row_number,name FROM table_name;

Answer 4

@vinoth我认为@Pragmatist答案对你有用。只需将此子句添加到他的查询中：

set @row_number = 0; 
select @row_number := @row_number + 1 as row_number,name FROM table_name Where name='b';

Answer 5

尝试以下方法。 MS SQL是一个经过测试的查询，我刚刚转换成了mysql。希望您可以根据您的要求进行修改。

    SET @rank=0;
    SELECT * FROM Table1 T1
    INNER JOIN(
           SELECT   @rank := @rank+1 AS rank, ID
           FROM     Table1
           ORDER BY id asc) temp ON temp.ID = T1.ID
    WHERE T1.name = 'd'

MS SQL查询将

SELECT * FROM Table1 T1
INNER JOIN(SELECT id, ROW_NUMBER() OVER (Order by id) AS RowNumber from Table1) temp ON   temp.ID = T1.ID
WHERE T1.name = 'd'

计算具有特定条件的行

5 个答案: