What is SAP as a technology/skill?
SAP makes business suites or applications that can be used for managing business needs of companies. There are various modules in SAP and all these can be customized for different needs of companies. These modules are business solution products made by SAP AG. For example, take SAP HR Payroll, apparently any company in this world can use this for generating employee pay slips, but laws and salary structure differ from country to country and company to company, all this needs certain level of customization. SAP sells these products and services companies like IBM, TCS implement them for companies. The time taken for initial implementation for these suites can be as long as year or two depending on the size of data to be migrated. Supposing the company was using paper/book for managing the processes, the time period can be longer, as it has to be designed by consultants after understanding the needs of the client. And most importantly the client has to agree to the solution. These module