Mass-metallicity relation for the host of GRB 190114C and other long GRB hosts. As comparison samples we plot data from SDSS DR15 (z = 0 − 0.32) (https://www.sdss.org/dr15/), the KMOS3D sample (z = 0.6 − 2.7, Wuyts et al. 2016), extreme emission-line galaxies found in the VVDS (z = 0 − 0.9, Amorín et al. 2014) and the MASSIVE sample (z = 0.9 − 2.2, galaxies from the VVDS sample followed up by SINFONI, Contini et al. 2012) (http://cosmosdb.iasf-milano.inaf.it:8080/VVDS-SINFONI/). We only plot galaxies up to a redshift of 2.1 for better visualisation. All metallicities except those in the Amorín et al. (2014) EELG sample are derived from the N2 parameter and the Marino et al. (2013) calibration. Amorín et al. (2014) metallicities were derived with the T_e method. We also plot the MZ relations at z = 0.07 (Zahid et al. 2013), z = 0.9 and z = 2.3 (Wuyts et al. 2014), which are also based on N2 parameter metallicities. The MZ relations were corrected for the difference in metallicity calibrators.