trdsql stdin

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stdin

trdsql can receive data from standard input like other UNIX tools. However, you need to specify the table name in SQL syntax. When using standard input, use “-” or “stdin”.

cat test.csv|trdsql -icsv "SELECT * FROM -"

apple,100
orange,50
potato,30
Details

trdsql receives standard input, but the execution of SQL starts after all standard input is received. Therefore, you cannot receive output from a command that does not end.

Commands that output CSV, LTSV, and JSON can be used directly by using standard input instead of a file name. For example, you can use it as it is by changing the character code to UTF-8 from a file that is not UTF-8, or

nkf -w sjis.csv|trdsql -icsv "SELECT * FROM -"

You can also try processing only the first few lines before processing a large file.

head -100 big.csv|trdsql -icsv "SELECT * FROM -"

In addition, there are many commands that output data that can be treated as table data if interpreted as a space-separated output in UNIX commands.

For example, the ps command,

$ ps
  PID TTY          TIME CMD
 1157 pts/3    00:00:00 ps
22590 pts/3    00:00:03 zsh

has a header and outputs each column (trdsql behaves to interpret consecutive spaces as one delimiter).

Therefore, you can output it in Ascii Table format as follows.

ps|trdsql -ih -id " " -oat "SELECT \`PID\`, \`TTY\`, \`TIME\`, \`CMD\` FROM -"

+-------+-------+----------+--------+
|  PID  |  TTY  |   TIME   |  CMD   |
+-------+-------+----------+--------+
|  1363 | pts/3 | 00:00:00 | ps     |
|  1364 | pts/3 | 00:00:00 | trdsql |
| 22590 | pts/3 | 00:00:03 | zsh    |
+-------+-------+----------+--------+

stdin with -a

If you use the -a option, you can specify the table name and file type in the SQL syntax.

command | trdsql -ih -id " " -a -

$ ps|trdsql -id " " -ih -a -
The table name is -.
The file type is CSV.

Data types:
+-------------+------+
| column name | type |
+-------------+------+
| \`PID\`     | text |
| \`TTY\`     | text |
| \`TIME\`    | text |
| \`CMD\`     | text |
+-------------+------+

Data samples:
+---------+---------+----------+---------+
| \`PID\` | \`TTY\` | \`TIME\` | \`CMD\` |
+---------+---------+----------+---------+
|    3168 | pts/0   | 00:00:00 | ps      |
+---------+---------+----------+---------+

Examples:
trdsql -id " " -ih "SELECT \`PID\`, \`TTY\`, \`TIME\`, \`CMD\` FROM -"
trdsql -id " " -ih "SELECT \`PID\`, \`TTY\`, \`TIME\`, \`CMD\` FROM - WHERE \`PID\` = '3168'"
trdsql -id " " -ih "SELECT \`PID\`, count(\`PID\`) FROM - GROUP BY \`PID\`"
trdsql -id " " -ih "SELECT \`PID\`, \`TTY\`, \`TIME\`, \`CMD\` FROM - ORDER BY \`PID\` LIMIT 10"