How to write the mysql query for return 4 rows exactly

I want to display the 4 rows from the table. I have using following query

SELECT field_name FROM tbl_name WHERE col_name = 'value' LIMIT 4;

The table contains more than 4 values means it display the first 4 rows perfectly. But it less than 4 rows means I need the result for following result

It display 2 rows only means

field_name
row1
row2
row2
row1

It display 3 rows only means

field_name
row1
row2
row3
row1

How can i get this result?

---

像这样尝试

Select * from (

select * from tbl_name WHERE col_name = 'value' LIMIT 4
union all 
select * from tbl_name WHERE col_name = 'value' LIMIT 4
union all
select * from tbl_name WHERE col_name = 'value' LIMIT 4
union all
select * from tbl_name WHERE col_name = 'value' LIMIT 4) as table1   LIMIT 4

---

不是一个很好的解决方案，但它应该可以工作：您可以使用UNION ALL重复查询4次，并限制为4个结果：

SELECT * FROM (
    SELECT field_name FROM tbl_name WHERE col_name = 'value' LIMIT 4;
    UNION ALL
    SELECT field_name FROM tbl_name WHERE col_name = 'value' LIMIT 4;
    UNION ALL
    SELECT field_name FROM tbl_name WHERE col_name = 'value' LIMIT 4;
    UNION ALL
    SELECT field_name FROM tbl_name WHERE col_name = 'value' LIMIT 4;
) a LIMIT 4

---

SELECT Column_Name
FROM (
SELECT Column_Name, ROW_NUMBER() OVER (ORDER BY Column_Name) AS RowNum
FROM [dbo].[AttendanceLog]
) AS MyDerivedTable
 WHERE MyDerivedTable.RowNum BETWEEN 1 and 4

链接地址: http://www.djcxy.com/p/75334.html

上一篇: MySQL匹配（）反对（）

下一篇: 如何编写mysql查询以准确返回4行