There are many OLAP techniques that you can use for trend analysis, depending on your data and objectives. Time series analysis is a popular technique, which involves analyzing the data along the time dimension to identify trends, cycles, seasonality, and outliers. OLAP operations like slicing, dicing, drilling, and rolling can be used to select and aggregate data by different time periods. Functions such as lag, lead, growth, and percentage change can be employed to compare and calculate the data across different time periods. Segmentation analysis is another effective technique which examines other dimensions to identify segments or clusters of data that have similar or different characteristics or behaviors. OLAP operations such as slicing, dicing, pivoting, and filtering can be used to select and arrange the data by different dimensions. Rank, percentile, quartile, and standard deviation are some of the OLAP functions that can compare and measure the data within and across different segments. Correlation analysis is another useful technique that looks at multiple dimensions to detect relationships between different variables or factors. OLAP operations like slicing, dicing, drilling, and pivoting can be used to select and combine the data by different dimensions. Functions such as sum, average, count, and ratio can be used to aggregate and calculate the data across different dimensions.