sql - SQL查询在破折号之前显示字符串

Question

我想执行一个查询，该查询仅显示特定字段中破折号之前的所有字符串。

例如：

原始数据：AB-123

查询后：AB

Answer 1

您可以使用substr：

SQL> WITH DATA AS (SELECT 'AB-123' txt FROM dual)
  2  SELECT substr(txt, 1, instr(txt, '-') - 1)
  3    FROM DATA;

SUBSTR(TXT,1,INSTR(TXT,'-')-1)
------------------------------
AB

或regexp_substr（10g+）：

SQL> WITH DATA AS (SELECT 'AB-123' txt FROM dual)
  2  SELECT regexp_substr(txt, '^[^-]*')
  3    FROM DATA;

REGEXP_SUBSTR(TXT,'^[^-]*')
---------------------------
AB

Answer 2

您可以使用regexp_replace.

例如

    WITH DATA AS (
         SELECT 'AB-123' as text FROM dual
         UNION ALL
         SELECT 'ABC123' as text FROM dual
    )
    SELECT 
        regexp_replace(d.text, '-.*$', '') as result
    FROM DATA d;

会导致

    WITH DATA AS (
      2      SELECT 'AB-123' as text FROM dual
      3      UNION ALL
      4      SELECT 'ABC123' as text FROM dual
      5  )
      6  SELECT
      7     regexp_replace(d.text, '-.*$', '') as result
      8  FROM DATA d;

    RESULT
    ------------------------------------------------------
    AB
    ABC123

Answer 3

我发现这很简单

 SELECT distinct
        regexp_replace(d.pyid, '-.*$', '') as result
    FROM schema.table d;

pyID 列包含 ABC-123、DEF-3454

SQL 结果：

ABC DEF