MySQL语句在select语句中的子查询

我需要使用子查询命名查询中的列。我写了一个声明，在该SELECT部分子查询，但我收到以下错误消息（来自笨返回）：MySQL语句在select语句中的子查询

错误编号：1064

您的SQL语法错误;检查对应于你的MySQL服务器版本使用附近的正确语法手册 '（SELECT ps_url_name FROM product_selects WHERE ps_id = '1'），psc_opt_2 A' 位于第1行

SELECT 
    `psc_opt_1` AS (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '1'), 
    `psc_opt_2` AS (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '2'), 
    `psc_opt_3` AS (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '3'), 
    `psc_opt_4` AS (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '4'), 
    `psc_opt_5` AS (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '5') 
FROM (`product_stock_control`) 
WHERE `psc_prod_id` = '5'

文件名：车型/ products_model.php

行号：602

任何想法是什么问题呢？

来源

2012-08-09 Phil Young

有PHP的功能，让你从一个表中提取列名....你有没有检查出来？它看起来像你在一些PHP代码中执行这个 – CheeseConQueso 2012-08-09 16:58:58

AS是列别名运算符，这意味着您选择这些变量作为标识符。您不能使用操作员通过查询识别变量。

参考：http://dev.mysql.com/doc/refman/5.0/en/problems-with-alias.html

相反，你需要扭转你如何使用别名操作符，像这样：

SELECT 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '1') AS `psc_opt_1`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '2') AS `psc_opt_2`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '3') AS `psc_opt_3`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '4') AS `psc_opt_4`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '5') AS `psc_opt_5` 
FROM (`product_stock_control`) 
WHERE `psc_prod_id` = '5'

理想情况下，你应该避免使用子查询（尤其是在这种情况下）以避免表锁定开销。

来源

2012-08-09 16:57:18

正确格式为

(SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '1') As `psc_opt_1`

来源

2012-08-09 16:58:20

你试试这个：

SELECT 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '1') as `psc_opt_1`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '2') as `psc_opt_2`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '3') as `psc_opt_3`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '4') as `psc_opt_4`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '5') as `psc_opt_5` 
FROM (`product_stock_control`) 
WHERE `psc_prod_id` = '5'

来源

2012-08-09 16:59:01 Taryn

你想命名此列psc_opt_1到psc_opt_1或什么什么，你到底要什么？

命名会是这样的：

SELECT 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '1') AS `psc_opt_1`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '2') AS `psc_opt_2`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '3') AS `psc_opt_3`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '4') AS `psc_opt_4`, 
    (SELECT `ps_url_name` FROM `product_selects` WHERE `ps_id` = '5') AS `psc_opt_5` 
FROM (`product_stock_control`) 
WHERE `psc_prod_id` = '5'

来源

2012-08-09 17:03:08 landi

MySQL语句在select语句中的子查询

回答

相关问题