st: match variable across two tables

[Rongrong Zhang <r05zhang@gmail.com>]

Dear STATALISTER,

I have two tables:

Table 1 has 3 variables  I-O number, I-O Name ,   Related 1997 NAICS codes.

Table 2 has 1 variable 1997 NAICS codes.

I want to link these two tables based on NAICS code. However, the
level of details on NAICS code does not match one-to-one because the
tables come from different data source. My goal is to know which NAICS
code correspond to which I-O number. I can’t use Table 1 only, because
TABLE 2 is produced from Wharton Research Database which has company
level financial data – I will use later on.

By different details I mean : e.g.

table 1:

I-O number  I-O Name                  1997 NAICS codes

1110        Crop production

1111A0    Oilseed farming
         11111      11112

1111B0    Grain farming             11113      11114      11115
11116      11119

111200    Vegetable and melon farming
                   1112
111400 Greenhouse and nursery production
                1114
111910 Tobacco farming
                11191
111920 Cotton farming
                11192
1119A0 Sugarcane and sugar beet
      11193 111991
1119B0 All other crop farming
11194 111992 111998

in the above example, I present industry 1110 and its subindustries
1111A0, 1111B0, 111200, each of the subindustries correspond to a few
(or a single) NAICS code (north america industry classification
system).

table 2:
NAICS CODE
111
1111
111150
111199
111219
111310
111320
111332
111334
111335
111339
1114
111411
111419
111421
111422
111920
111930
111940
111998

if I enforce exact match, then table 2  111150 matches with table 1
1111B0,    table 2 1112l9 may be matched with  111200 table 1 I-O.

My question :
1.could you give a sample code/function to do exact match? note, if
first 5digit match, and drop last 0 (naics), we consider that a match
2. if I want to increase match, how could I change the program to do 4
digit match

thanks a bunch,

-- 
Best,
Rochelle

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