如何将utf8的表转为utf8mb4

ALTER TABLE xxx CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
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打印log中某一列

例如包含userId的
awk -F '\t' '{for(i=1; i<=NF; i++){if ($i ~ /.*user_id.*/){print $i}}}'
[......]

sort filename | uniq -c | sort -nr
[......]

首先要排序
#find lines only in file1
comm -23 file1 file2

#find lines only in file2
comm -13 file1 file2

#find lines common to both files
comm -12 file1 file2
[......]

byte[] -> int
int result = ByteBuffer.wrap(bytes).getInt();
int -> byte[]
byte[] bytes = ByteBuffer.allocate(4).putInt(1695609641).array();

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