MySQL CONCAT 表过滤语法答案

【问题标题】：MySQL CONCAT table filtering syntaxMySQL CONCAT 表过滤语法
【发布时间】：2015-03-14 04:19:37
【问题描述】：

我收到一个错误“错误代码：1064。您的 SQL 语法有错误；请查看与您的 MySQL 服务器版本相对应的手册，以了解在“ORDER BY p.@”附近使用的正确语法987654321@ ASC' at line 1" 在我的 order by 子句中，我不确定为什么，当我取消 CONCAT 查询时，它似乎工作正常。

我错过了什么吗？这是我的代码：

    SET _select = CONCAT( "SELECT p.`promo_code` AS code, p.`name` AS username, p.`company` AS company " );
    SET _select = CONCAT( _select, " FROM `promos` AS p" );

    SET _where = CONCAT( " WHERE 1 = 1");

    IF _promoCode IS NOT NULL THEN
        SET _where = CONCAT( _where, " AND ( p.`promo_code` LIKE '%", _promoCode, "%'" );
    END IF;
    IF _companyName IS NOT NULL THEN
        SET _where = CONCAT( _where, " AND ( p.`company` LIKE '%", _companyName, "%'" );
    END IF;
    IF _userName IS NOT NULL THEN
        SET _where = CONCAT( _where, " AND ( p.`name` LIKE '%", _userName, "%'" );
    END IF;

    -- SET _where_total = _where;

    #SORT option protocols, 1 is promocode, 2 is company, 3 is name; Second number is ASC/DESC
    IF _sortOrder IS NOT NULL THEN
        CASE _sortOrder
            WHEN 10 THEN
                SET _where = CONCAT( _where, " ORDER BY p.`promo_code` ASC" );
            WHEN 11 THEN
                SET _where = CONCAT( _where, " ORDER BY p.`promo_code` DESC" );
            WHEN 20 THEN
                SET _where = CONCAT( _where, " ORDER BY p.`company` ASC" );
            WHEN 21 THEN
                SET _where = CONCAT( _where, " ORDER BY p.`company` DESC" );
            WHEN 30 THEN
                SET _where = CONCAT( _where, " ORDER BY p.`name` ASC" );
            WHEN 31 THEN
                SET _where = CONCAT( _where, " ORDER BY p.`name` DESC" );
            ELSE
                SELECT "Please use valid sort protocol";
        END CASE;
    END IF;

    /*SET _where = CONCAT( _where, " LIMIT ", _start, ", ", _records );*/

    SET @query = CONCAT( _select, _where );

    PREPARE stmt FROM @query;
    EXECUTE stmt;
    DEALLOCATE PREPARE stmt;

    SET _select_total = "SELECT COUNT( p.`promo_code` ) AS total_matching_promos ";
    SET _select_total = CONCAT( _select_total, " FROM `promos` AS p " );

    SET @query = CONCAT( _select_total, _where_total );

    PREPARE stmt FROM @query;
    EXECUTE stmt;
    DEALLOCATE PREPARE stmt;

【问题讨论】：

标签： mysql sql syntax syntax-error concatenation

【解决方案1】：

发现问题。

条件 WHERE 子句中有一些左括号：

IF _promoCode IS NOT NULL THEN
    SET _where = CONCAT( _where, " AND **(** p.`promo_code` LIKE '%", _promoCode, "%'" );
END IF;
IF _companyName IS NOT NULL THEN
    SET _where = CONCAT( _where, " AND **(** p.`company` LIKE '%", _companyName, "%'" );
END IF;
IF _userName IS NOT NULL THEN
    SET _where = CONCAT( _where, " AND **(** p.`name` LIKE '%", _userName, "%'" );
END IF;

删除这些并移动SET _where_total = _where; 就在SET @query = CONCAT( _select, _where );

之前

不要盲目复制粘贴代码的人：P

【讨论】：