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Using the SDSS spectra of quasars included in the DR7Q or DR12Q catalogs, wesearch for Mg II narrow absorption doublets in the spectra data around Mg IIemission lines. We obtain 17,316 Mg II doublets, within the redshift range of0.3299<= z_abs <= 2.5663. We find that a velocity offset of v_r < 6000 km/s isa safe boundary to constrain the vast majority of associated Mg II systems,although we find some doublets at v_r > 6000 km/s. If associated Mg IIabsorbers are defined by v_r < 6000 km/s, ~33.3% of the absorbers supposed tobe contaminants of intervening systems. Removing the 33.3% contaminants, ~4.5%of the quasars present at least one associated Mg II system withW_r\lambda2796>=0.2 \AA. The fraction of associated Mg II systems with highvelocity outflows correlates with the average luminosities of their centralquasars, indicating a relationship between outflows and the quasar feedbackpower. The v_r distribution of the outflow Mg II absorbers is peaked at 1023km/s, which is smaller than the corresponding value of the outflow C IVabsorbers. The redshift number density evolution of absorbers (dn/dz) limitedby v_r > -3000 km/s differs from that of absorbers constrained by v_r > 2000km/s. While, absorbers limited by v_r > 2000 km/s and higher values exhibitsimilar profile of dn/dz. In addition, the dn/dz is smaller when absorbers areconstrained with larger v_r. The distributions of equivalent widths, and theratio of W_r\lambda2796/W_r\lambda2803 is the same for associated andintervening systems, and independent on quasar luminosity.

The associated absorption features in quasar spectra of the Sload Digital Sky survey .I. \MgII\ absorption doublets