MySQL如果数字选择其他列

Question

是否有mysql函数来检查值是否只是数字？

我不想CONCAT 2列， 如果tbl3.column2是数字，然后concat与其他表列，如果字符串然后相同的表其他列将做。

SELECT tbl1.column1 as Column1, tbl2.column2 as Column2, 
IF tbl3.column2 REGEXP '^[0-9]+$' THEN CONCAT(tbl3.column1, ' ', tbl4.column1) ELSE CONCAT(tbl3.column1, ' ', tbl3.column2) END IF as Combined 
FROM table1 tbl1 
LEFT JOIN table2 tbl2 ON tbl1.id = tbl2.id 
LEFT JOIN table3 tbl3 ON tbl3.id = tbl1.id 
LEFT JOIN table4 tbl4 ON tbl4.id = tbl1.id 
LEFT JOIN table5 tbl5 ON tbl5.id = tbl1.id 
WHERE 
tbl5.column3 = ? 
ORDER BY Column1 ASC 

当前的代码提供错误：

You have an error in your SQL syntax; check the manual that corresponds 
to your MySQL server version for the right syntax to use near 'tbl3.column2 REGEXP '^[0-9]+$' 
    THEN CONCAT(tbl3.column1, ' ', tbl4.column1' at line 

Answer 1

试试这个请：

SELECT tbl1.column1 AS Column1, tbl2.column2 AS Column2, 
IF(tbl3.column2 REGEXP '^[0-9]+$' 
    , CONCAT(tbl3.column1, ' ', tbl4.column1) 
    , CONCAT(tbl3.column1, ' ', tbl3.column2) 
    ) AS Combined 
FROM table1 tbl1 
LEFT JOIN table2 tbl2 ON tbl1.id = tbl2.id 
LEFT JOIN table3 tbl3 ON tbl3.id = tbl1.id 
LEFT JOIN table4 tbl4 ON tbl4.id = tbl1.id 
LEFT JOIN table5 tbl5 ON tbl5.id = tbl1.id 
WHERE 
tbl5.column3 = ? 
ORDER BY Column1 ASC