Information that is easily leaked in SQL
The string in the WHERE clause and the value in the INSERT statement are noticeable, but the business content can also be inferred from identifiers such as customer_contract and employee_salary. Connection destination name, schema name, comment, and stored procedure name are also checked.
- Values such as customer number, name, address, email address, etc.
- Schema name and table name including internal system name
- Column names, constants, and comments that explain business rules
- Connection string, DB link, hostname, file path
Steps to replace without destroying the structure
- Copy only the SQL statements needed for investigation and separate connection settings and execution logs.
- Decide which categories to mask: tables, columns, values, and comments.
- Use the same replacement for each occurrence of an identifier so JOINs and subqueries remain consistent.
- Select the target DB and check whether DB specific expressions such as quotation marks, functions, and paging syntax remain.
Points to check before sharing
| Item | What to Verify |
|---|---|
| syntax | Are there any missing parentheses, quotation marks, or terminal symbols? |
| Identifier Mapping | Do aliases, JOIN conditions, and CTE references have the same replacement name? |
| Values | Is there any actual data remaining in the date, ID, LIKE condition, or IN clause? |
| Comments | Are the contact person's name, problem number, and customer name left? |
Treat masked SQL as a copy for sharing; do not run it against a production database. If execution testing is necessary, use an isolated environment with test data.
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