% @(#)join_tabl.hlq	17.1.1.1 (ESO-IPG) 01/25/02 17:43:42
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1990 European Southern Observatory
%.IDENT      join_tabl.hlq
%.AUTHOR     MP, IPG/ESO
%.KEYWORDS   MIDAS, help files, JOIN/TABLE
%.PURPOSE    On-line help file for the command: JOIN/TABLE
%.VERSION    1.0  9-SEP-1992 : Creation, MP
%----------------------------------------------------------------
\se
SECTION./TABL
\es\co
JOIN/TABLE						09-SEP-1992  MP
\oc\su
JOIN/TABLE intab1 :X1,[:Y1] intab2  :X2,[:Y2] outtable [tolX,tolY]
	join table files
\us\pu
Purpose:    
         Find common objects in two tables by comparing one or two 
         attributes
\up\sy
Syntax:  
         JOIN/TABLE intab1 :X1,[:Y1] intab2 :X2,[:Y2] outtable [tolX,tolY]
\ys\pa
         intab1    = first input table 
\ap\pa
         :X1,:Y1   = columns of the table intable1 to be looked at 
\ap\pa
         intab2    = second input table
\ap\pa
         :X2,:Y2   = columns of the table intable2 to be looked at 
\ap\pa
         outtable  = output table
\ap\pa 
         tolX,tolY = tolerance for the error. defaulted to 0,0
\\
                     only valid for numerical columns
\ap\no
Note:       
         The command joins table files, that is it finds common objects in 
         two tables by comparing one or two attributes (columns of the 
         table) of the objects (rows of the table) from both files, given
         an uncertainty for each attribute. In the exact match (uncertainty
         equal to 0) objects with identical attributes are identified
         as being the same object. In the approximate match, the attributes
         have to be the same within a certain tolerance.    
         Only exact match can be performed on character strings columns. 
         The (numerical) columns which are compared don't need to be of
         the same type: the match will be done in double precision.
         The output table will contain as many rows as the number of 
         common objects which are found. It will contain all the columns
         of the first table as well as the ones from the second table.
         The columns will get the labels laborig_n where laborig is the
         label of the column in the input table and n the number of the 
         input table. 
\\
         The biggest of the two input tables should be given in the command
         line as second input table (intab2)
\on\exs
Examples:
\ex
         JOIN/TABLE zcat :RA,:DEC rc3 :RA,:DEC zcat_rc3 0.01,0.01
           Find the common objects from the tables `rc3.tbl' and `zcat.tbl' by
           comparing their columns RA and DEC. Objects having similar
           coordinates within a error box or 0.01*0.01 will be identified as
           common and all their attributes will be copied into the table
           `zcat_rc3.tbl'.
\xe \sxe