The Table Query Language (TaQL) is an SQL-like high level language to do operations like selection, sort, and update on a casacore table. It is a very versatile language with full support for table columns containing array data. It has inherent support for masked arrays, units, and astronomical coordinates. It has a very rich set of functions (like cone search and array reduction) making it very suitable for astronomical applications. User defined functions can be added easily. It also has full support of grouping/aggregation and nested queries. An operation that can be expressed in a single function is the matching of two sky catalogues.
taql can be started with multiple arguments containing options and an optional TaQL command as the last argument. It will run interactively if no TaQL command is given. If possible, interactive commands are kept in $HOME/.taqlhistory for later reuse.
A binding in C++, Python, and Glish is available.
- defines the TaQL style. The default style is python; if no value is given after -s it defaults to glish.
- show help and exits.
- show the values of selected columns.
- if possible, show values as formatted measures.
- show the (expanded) TaQL command.
- show the number of rows selected, updated, etc.
The default for -pc is on for interactive mode, otherwise off. The default for -pr, -ps, and -pm is on.
This manual page was written by Benda Xu <[email protected]>, for the Debian GNU/Linux system.