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我想變換PostgreSQL的列:無效的長度:場上位置必須大於零
下面是爲col_a一些值:
col_A
---------
John_arrived
Mary_Brown_arrived
J_C_Jr_arrived
Q_arrived
的目的是讓第一部分和只爲col_a的最後一部分:
d_col_A
-------
John_arrived
Mary_arrived
J_arrived
Q_arrived
這裏是我的查詢:
with t1 as (
select split_part(col_A, '_'::text, 1) || '_'
|| COALESCE (split_part(col_A, '_'::text, -1), '') as d_col_A
from my_table
)
select distinct d_col_A from t1
然後我得到了以下錯誤:
Invalid Length
Detail:
-----------------------------------------------
error: Invalid Length
code: 8001
context: field position must be greater than zero
query: 2382655
location: funcs_string.cpp:1565
process: query0_27 [pid=11502]
-----------------------------------------------
任何想法,我做錯了什麼?謝謝!