如何使mysql数据库表中选定行的第一行为空 [英] how to make empty first row of selected rows in mysql database table

问题描述

问题:

如何使 MySQL 数据库表中选定行的第一行为空或为空.

注意:

如果从mysql数据库表中选择时第一行有值也应该为空或空.

示例表

<前>身份证姓名年龄1 拉姆库马尔 242 迪内什 263 古普塔 25

选择表格时预期的表格格式

<前>身份证姓名年龄1 0 242 迪内什 263 古普塔 25

注意:以上我在选择时期望 0 而不是 Ramkumar

解决方案

试试这个

SELECT ID ,CASE WHEN row_number = 1 Then '0' ELSE Name END AS Name ,年龄从(选择 l.ID 作为 ID，l.Name AS Name,l.Age AS 年龄，@curRow := @curRow + 1 AS row_number从表1 l加入 (SELECT @curRow := 0) r) 作为

或:

SELECT CASE WHEN row_number = 1 Then NULL ELSE ID END AS ID ,CASE WHEN row_number = 1 Then NULL ELSE Name END AS Name ,CASE WHEN row_number = 1 Then NULL ELSE Age END AS Age从(选择 l.ID 作为 ID，l.Name AS Name,l.Age AS 年龄，@curRow := @curRow + 1 AS row_number从表1 l加入 (SELECT @curRow := 0) r) 作为

Question:

How to make empty or null of first row of selected rows in MySQL database table.

NOTE:

if first row having value also should make empty or null while selecting from mysql database table.

Sample Table

ID     Name       Age
1      Ramkumar   24
2      Dinesh     26
3      Gupta      25

Expected Table Format While Selecting Table

ID     Name       Age
1      0          24
2      Dinesh     26
3      Gupta      25

NOTE: Above i am expecting 0 instead of Ramkumar while selecting

解决方案

Try this

SELECT ID ,
       CASE WHEN row_number = 1 Then '0' ELSE Name END AS Name , 
       Age 
FROM 
(
SELECT  l.ID AS ID, 
        l.Name AS Name, 
        l.Age AS Age,
        @curRow := @curRow + 1 AS row_number
FROM    Tabe1 l
JOIN    (SELECT @curRow := 0) r
) AS T

OR:

SELECT CASE WHEN row_number = 1 Then NULL ELSE ID END AS ID ,
       CASE WHEN row_number = 1 Then NULL ELSE Name END AS Name , 
       CASE WHEN row_number = 1 Then NULL ELSE Age END AS Age 
FROM 
(
SELECT  l.ID AS ID, 
        l.Name AS Name, 
        l.Age AS Age,
        @curRow := @curRow + 1 AS row_number
FROM    Tabe1 l
JOIN    (SELECT @curRow := 0) r
) AS T

这篇关于如何使mysql数据库表中选定行的第一行为空的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！