Question

我的查询类似于：

SELECT
  s.cola, s.colb, t.colc, t.cold, u.cole, u.colf, u.colg, u.colh, u.coli, u.colj, u.colk, u.coll 
FROM table1 s
INNER JOIN table2 t
  ON s.colb = t.colc
INNER JOIN table3 u
  ON u.colm = t.cold
WHERE cast(s.cola as date) between date '2017-11-06' and date '2017-11-10'
ORDER BY 3

我需要添加一个名为col_new的新列，该列将由u.colm或u.coln填充。如果该列以数字开头，则此列将具有u.colm的值。否则它将具有u.coln的值。众所周知，对于表u.coln中的每个条目，u.colm或u都以数字开头。

我尝试了以下查询来测试是否可以识别以数字开头的条目：

SELECT CASE WHEN ISNUMERIC(SUBSTRING(LTRIM(colm), 1, 1)) = 1
        THEN 'yes'
        ELSE 'no'
      END AS col_new
FROM table_u

它返回了错误：Syntax error: expected something between '(' and the 'substring' keyword.

请提出解决方案。

修改确切错误：

[Teradata Database] [3706] Syntax error: expected something between '(' and the 'substring' keyword.

Answer 1

而不是isnumeric()，只需进行比较：

SELECT (CASE WHEN LEFT(LTRIM(colm), 1) BETWEEN '0' AND '9' THEN 'yes'
             ELSE 'no'
        END) AS col_new
FROM table_u;

LEFT()是字符串的第一个“n”字符的便捷简写。

Teradata - 根据是否以数字开头在两列之间进行选择

1 个答案: