Category Archives: sql Certificate

Khóa học miễn phí SQL – Using Single-Row Functions nhận dự án làm có lương

SQL – Using Single-Row Functions Using Single row functions to customize output Oracle SQL supplies a rich library of in-built functions which can be employed for various tasks. The essential capabilities of a functions can be the case conversion of strings, in-string or substring operations, mathematical computations on numeric data, and date operations on date […]

Khóa học miễn phí SQL – Using the Set Operators nhận dự án làm có lương

SQL – Using the Set Operators Set operators are used to join the results of two (or more) SELECT statements.The SET operators available in Oracle 11g are UNION,UNION ALL,INTERSECT,and MINUS. The UNION set operator returns the combined results of the two SELECT statements.Essentially,it removes duplicates from the results i.e. only one row will be listed […]