如何以及在哪里设置和检查group_concat_max_len

Question

For this query

CREATE TABLE IF NOT EXISTS users  (
columns.......
)

do I put SET GLOBAL group_concat_max_len = 999999 before or after creating the tables? And how can I check if it is actually SET to 999999 using a query like SHOW group_concat_max_len or something.

Answer 1

在执行SELECT查询之前，您具有SET group_concat_max_len 。