Finding what differs.
WHEN YOU NEED IT
Confirming a migration copied everything Comparing staging against production Finding what a plugin changed Investigating why two environments behave differently
COMPARING SIZE AND COUNTS
The quickest check. Compare the table list and row counts between the two.
SELECT COUNT(*) on key tables in each. A discrepancy tells you something is missing.
phpMyAdmin's structure view lists row counts per table, though for InnoDB these are estimates.
COMPARING STRUCTURE
Export the structure only, from both, and compare the files in a text comparison tool.
That reveals missing tables, missing columns and type differences.
COMPARING DATA
Harder. For specific rows, select them from each and compare.
For a wholesale comparison, export both and use a comparison tool, though large dumps make this unwieldy.
AFTER A MIGRATION
The practical check: table count, row counts on the main content tables, and a sample of records.
That catches the common failure of a truncated import.
WHEN IT MATTERS
Before decommissioning a source server. Confirm before you cancel.
