MySQL Cookbook

Specifying Arbitrary Output Column Delimiters

Problem

You want mysql to produce query output using a delimiter other than tab.

Solution

Postprocess mysql’s output.

Discussion

In non-interactive mode, mysql separates output columns with tabs and there is no option for specifying the output delimiter. Under some circumstances, it may be desirable to produce output that uses a different delimiter. Suppose you want to create an output file for use by a program that expects values to be separated by colon characters (:) rather than tabs. Under Unix, you can convert tabs to arbitrary delimiters by using utilities such as tr and sed. For example, to change tabs to colons, any of the following commands would work (TAB indicates where you type a tab character):^[8]

% mysql cookbook < inputfile  | sed -e "s/TAB/:/g" > outputfile
% mysql cookbook < inputfile  | tr "TAB" ":" > outputfile
% mysql cookbook < inputfile  | tr "\011" ":" > outputfile

sed is more powerful than tr because it understands regular expressions and allows multiple substitutions. This is useful when you want to produce output in something like comma-separated values (CSV) format, which requires three substitutions:

• Escape any quote characters that appear in the data by doubling them so that when you use the resulting CSV file, they won’t be taken as column delimiters.

• Change the tabs to commas.

• Surround column values with quotes.

sed allows all three subsitutions to be performed in a single command:

% mysql cookbook < inputfile ...