System.LimitException: Too many query rows: 50001 in salesforce - Salesforce Globe For You
Answer: For each Apex transaction,total number of records retrieved by SOQL queries whether synchronous or asynchronous is 50000.
If single or multiple soql queries are running in a single transaction and the total sum of records returned
by all queries in that single apex transaction exceeds 50000,then this error occurs.
Solution:
1)Use conditions in soql queries if possible to filter the records.
2) Use Batch Apex.
