The first parameter is the literal or column value on which you want the SUBSTR function to operate. The second parameter is the position of the starting character for the substring, and the optional third parameter is the number of characters to be included in the substring.If the third parameter is not specified, the SUBSTR function will return the remainder of the string.he second parameter is the position of the starting character for the substring, and the optional third parameter is the number of characters to be included in the substring. If the third parameter is not specified, the SUBSTR function will return the remainder of the string.
There are two basic types of metamorphic rocks. Foliated metamorphic rocks such as gneiss, phyllite, schist, and slate have a layered or banded appearance that is produced by exposure to heat and directed pressure. Non-foliated metamorphic rocks such as hornfels, marble, quartzite, and novaculite do not have a layered or banded appearance.
Gneiss Gneiss is a hard rock that has a mineral composition similar to granite as it contains the feldspar, mica, and quartz. This is a rock that is formed from pre-existing igneous rocks such as granite that have been subject to conditions of high pressure and temperature.