Tell me about how you would solve these tasks: combine two tables using pandas and plot the data, check if a string is a palindrome, reverse a substring in a string, and count and display the frequency of each character in a string.
For SQL, treat each row as a text record and produce the equivalent joined and derived result. Ignore spaces and non-alphanumeric characters when calculating character frequencies. The plotting step is outside SQL; return data suitable for plotting.
| Column | Type | Description |
|---|---|---|
| record_idPK | INT | Unique identifier for the text record |
| text_value | VARCHAR(255) | Text value to analyze |
| Column | Type | Description |
|---|---|---|
| record_idPK | INT | Identifier matching a text record |
| label | VARCHAR(50) | Optional metadata label |