Dear Madam/Sir,

I run the following regression and want to use only observations (77,626) that regression is run to generate descriptive statistics. The original dataset is over 100,000 observations.

regress ln_change_sga ln_change_sale ln_bw lnbw_change_sale uncertain gdprate sec_dec asset_int EMP_int uncertian_change_sale gdpg_change_sale sec_dec_sale asset_int_sale emp_int_sale i.sic2 i.fyear, robust cluster(gvkey)

Number of obs = 77,626

Is the following command the only way to use 77,626 observation? It also generates invalid syntax error.
drop if ln_change_sga==. |ln_change_sale ==.| ln_bw==.| lnbw_change_sale==.| uncertain==.| gdprate==.| sec_dec==.| asset_int==.| EMP_int==.| uncertian_change_sale==.| gdpg_change_sale==.| sec_dec_sale==.| asset_int_sale==.| emp_int_sale==.|

invalid syntax

Any help will be highly appreciated.

Joon