应用程序没有启动画面Xcode 5(App without splash screen Xcode 5)

 所以基本上你可以将你的问题视为列的连接，如果它们与^\d+$正则表达式不匹配，否则为空字符串。 您可以在MySQL文档中找到有关REGEXP ， CONCAT和CASE的更多文档，但下面有代码，可能会引导您实现您想要实现的目标： 
 
SELECT
    CONCAT(
    CASE WHEN a REGEXP '^[[:digit:]]+$' THEN '' ELSE a END,
    CASE WHEN b REGEXP '^[[:digit:]]+$' THEN '' ELSE b END,
    CASE WHEN c REGEXP '^[[:digit:]]+$' THEN '' ELSE c END,
    CASE WHEN d REGEXP '^[[:digit:]]+$' THEN '' ELSE d END) as result
FROM your_table;
 
 当然你可以使用NOT REGEXP ，但对我来说这样更清楚。 

So basically you may look at your problem as concatenation of columns if they do not match ^\d+$ regular expression or empty string otherwise. You may find more documentation on REGEXP, CONCAT and CASE in MySQL docs, but below there is code, that may lead you to what you want to achieve:
 
SELECT
    CONCAT(
    CASE WHEN a REGEXP '^[[:digit:]]+$' THEN '' ELSE a END,
    CASE WHEN b REGEXP '^[[:digit:]]+$' THEN '' ELSE b END,
    CASE WHEN c REGEXP '^[[:digit:]]+$' THEN '' ELSE c END,
    CASE WHEN d REGEXP '^[[:digit:]]+$' THEN '' ELSE d END) as result
FROM your_table;
 
Of course you may use NOT REGEXP instead, but for me it's clearer this way.