SQL Regex Replace

What is the SQL Regex Replace Tool?

The SQL Regex Replace tool applies regular-expression find-and-replace across your SQL text, making batch refactoring quick and safe. Instead of editing dozens of table or column names by hand, you write one pattern and let the tool rewrite every match at once. You can scope the replacement to the entire SQL, table names only, column names only, or comments only, and toggle the g (global), i (case-insensitive), and m (multiline) flags. Before anything is changed, the preview panel lists every match so you can verify exactly what will be rewritten, and every operation can be undone while the original SQL is always preserved. It uses JavaScript's RegExp engine — supporting groups, backreferences ($1, $2), alternation, quantifiers, and word boundaries — and runs entirely in your browser. Because every replacement is recorded in a history stack, you can step backward through the undo log and restore the original input at any point, so no mistake is ever permanent. The four example presets — adding a table prefix, renaming columns, cleaning comments, and converting snake_case to camelCase — double as a quick tutorial for the most common refactors.

How to Refactor SQL with Regex

1. Paste your SQL into the Input SQL text area.
2. Enter a regular expression in the Find (regex) field and the replacement text in Replace with.
3. Choose a scope — Entire SQL, Table Names, Column Names, or Comments — and set the flags you need.
4. Click Preview Changes and review the list of matches before continuing.
5. Click Apply Replace to commit the change, then copy the result or use it as a new input for another pass.

Common Use Cases

• Adding a schema prefix to every table name in a script with a single pattern.
• Renaming a shared column prefix such as customer_ to cust_ throughout a query.
• Stripping -- and block comments to clean up code before shipping.
• Converting snake_case identifiers to camelCase with a capture-group replacement.
• Standardizing inconsistent naming across a large migration script.
• Rewriting table aliases or identifiers in a generated query you want to reuse.

Example: Adding a Table Prefix

To prefix every table name with app_, set the scope to Table Names and use the pattern (users|orders|products) with the replacement app_$1:

Only the table references change; column names and aliases stay untouched because the replacement is scoped to table names.

Tips for Safe Regex Refactoring

Always run a Preview before applying, and prefer the narrowest scope that fits your goal — a pattern like id on Entire SQL will match far more than you expect. Use word-boundary anchors (\b) to avoid partial matches, and capture groups ($1, $2) to reuse parts of each match in the replacement. If a pattern behaves unexpectedly, remember the tool uses JavaScript's RegExp engine, so features like lookbehind may not be available in every browser. For multi-step refactors, use the "Use as New Input" button to chain replacements together without losing your place.

Frequently Asked Questions

How does the SQL regex replace tool work?

Paste your SQL, enter a regex pattern and replacement text, then click Preview to see all matches highlighted. You can scope the replacement to table names only, column names only, comments only, or the entire SQL. Each replacement is shown individually so you can verify before applying. All processing happens in your browser.

Can I batch rename multiple tables at once?

Yes. Set the scope to Table Names and use a regex like (orders|users|products) with a replacement like new_$1_schema. All matching table references across the entire SQL will be renamed in one operation. The preview shows each match before you commit.

Is there an undo function?

Yes. Every replace operation is tracked. You can undo the last replace or reset to the original SQL at any time. The tool keeps the original input so you never lose your starting query.

What regex flavor does this tool use?

The tool uses JavaScript's RegExp engine (ECMAScript regex). This supports all standard features: character classes, groups, backreferences ($1, $2...), alternation, quantifiers, lookaheads, and word boundaries. Flags like g (global) and i (case-insensitive) are exposed as toggles.

Is my SQL data sent to a server?

No. All regex matching, previewing, and replacement runs entirely in your browser using client-side JavaScript. Nothing is transmitted, stored, or logged. This makes it safe for proprietary SQL and schema information.

Can I use regex replace to strip SQL comments or normalize whitespace?

Yes. Set the scope to Comments Only to remove line comments and block comments, or use the Entire SQL scope with a pattern like \s+ to collapse runs of whitespace. Preview first: comment markers can also appear inside string literals, so check the highlighted matches before applying.

Does it work on large dumps and INSERT statements?

Yes. The tool runs client-side, so multi-megabyte mysqldump files and long INSERT statements can be refactored in place. For very large scripts, scope the replacement to Table Names or Column Names instead of Entire SQL to keep the preview fast and the operation precise.