利用Shell脚本将MySQL表中的数据转化为json格式

#!/bin/bash
mysql -s -phello test >1.log <<EOF
desc t1;
EOF
lines="concat_ws(',',"
count=`cat 1.log|wc -l`
linenum=0
while read line
do
 coloumname=`echo $line |awk '{print $1}'`
 let linenum=linenum+1
  if [ $linenum -eq 1 ];then
    lines=$lines"concat_ws(':','{"'"'$coloumname'"'"',if("$coloumname" is null or $coloumname='','null',concat('"'"'"',$coloumname,'"'"'"')))"
 elif [ $linenum -eq $count ];then
    lines=$lines",concat_ws(':','"'"'$coloumname'"'"',if("$coloumname" is null or $coloumname='','null}',concat('"'"'"',$coloumname,'"'"'"}'))))"
 else
    lines=$lines",concat_ws(':','"'"'$coloumname'"'"',if("$coloumname" is null or $coloumname='','null',concat('"'"'"',$coloumname,'"'"'"')))"
  fi
done < 1.log
echo $lines

mysql> select * from t1;
+------+-------+
| id   | name  |
+------+-------+
|    1 |       |
|    1 | NULL  |
|    2 | hello |
+------+-------+
3 rows in set (0.00 sec)

concat_ws(',',concat_ws(':','{"id"',if(id is null or id='','null',concat('"',id,'"'))),concat_ws(':','"name"',if(name is null or name='','null}',concat('"',name,'"}'))))

mysql> select concat_ws(',',concat_ws(':','{"id"',if(id is null or id='','null',concat('"',id,'"'))),concat_ws(':','"name"',if(name is null or name='','null}',concat('"',name,'"}')))) json_format from t1;
+---------------------------+
| json_format               |
+---------------------------+
| {"id":"1","name":null}    |
| {"id":"1","name":null}    |
| {"id":"2","name":"hello"} |
+---------------------------+
3 rows in set (0.00 sec)