快速进行有趣主题的即兴演奏会
这里有潜在的无限真实应用案例组合,以下是几个变化:
#standardSQL
WITH data AS (
SELECT 'a' a, 'b' b, 'c' c UNION ALL
SELECT 'y', 'x', NULL UNION ALL
SELECT 'v', NULL, 'w'
)
SELECT
*,
CONCAT(a, b, c) by_concat,
ARRAY_TO_STRING([a,b,c], '') by_array_to_string,
ARRAY_TO_STRING([a,b,c], '', '?') with_null_placeholder,
ARRAY_TO_STRING(
(SELECT ARRAY_AGG(col ORDER BY col DESC)
FROM UNNEST([a,b,c]) AS col
WHERE NOT col IS NULL)
, '') with_order
FROM `data`
输出结果为:
a b c by_concat by_array_to_string with_null_placeholder with_order
-
y x null null yx yx? yx
a b c abc abc abc cba
v null w null vw v?w wv
SELECT ARRAY_TO_STRING([a,b,nu], '')
。 - Mikhail Berlyant