Features
“SQL contains string” refers to techniques for checking whether a column value includes a given substring, most often implemented with LIKE, PATINDEX, CHARINDEX, INSTR, or POSITION.
“SQL contains string” means detecting whether a text column includes a substring. Most engines solve this with the LIKE pattern operator or a string-search function such as CHARINDEX (SQL Server), INSTR (MySQL/Oracle), or POSITION (PostgreSQL).
LIKE evaluates patterns with two wildcards: % matches any length sequence; _ matches a single character. Example: WHERE name LIKE '%smith%'. The query returns every name that contains “smith” anywhere inside the string.
String-search functions return the starting index of the substring or 0 if absent. They are useful when you need the position or want to embed the search inside CASE expressions: SELECT * FROM posts WHERE CHARINDEX('sql', body) > 0.
Most databases depend on collation settings for case sensitivity. Force case-insensitive search by lowering both sides: WHERE LOWER(title) LIKE LOWER('%galaxy%'). PostgreSQL supports ILIKE for case-insensitive patterns.
Combine conditions with OR: WHERE description LIKE '%error%' OR notes LIKE '%error%'. Wrap in COALESCE for nullable columns: WHERE COALESCE(description,'')||COALESCE(notes,'') LIKE '%error%'.
Leading wildcards ("%abc") disable index seeks and cause full scans. Prefer right-anchored patterns ('abc%') or full-text indexes. For frequent substring filtering, add a functional index on LOWER(column) or use trigram indexes in PostgreSQL.
Always bind parameters instead of string concatenation to avoid SQL injection. Example in Python: cur.execute('SELECT * FROM users WHERE email ILIKE %s', ('%' + keyword + '%',))
Galaxy’s AI copilot autocompletes LIKE patterns, warns about leading wildcards, and offers indexed alternatives. In the desktop SQL editor, type “contains” and the copilot suggests the best engine-specific function instantly.
DevOps teams search logs for “timeout” using: SELECT * FROM logs WHERE message LIKE '%timeout%'. Galaxy users store and endorse this query in a Collection so teammates reuse it instead of pasting into Slack.
Prefer LIKE for simple cases; use engine-specific functions when you need positions. Avoid leading wildcards for performance. Use parameterization for safety. Consider full-text or trigram indexes for large datasets.
Substring searches drive analytics, data quality checks, and customer experience. Engineers flag error patterns, marketers tag user content, and data scientists filter free-text fields. Mastering the right operator prevents slow full-table scans, protects against injection, and shortens debug cycles. Fast, accurate text filtering is therefore foundational to reliable data pipelines.
Performance is similar when patterns are sargable (no leading wildcards). Both can use indexes. Difference appears when you need position; functions then add extra CPU.
Create full-text, trigram, or expression indexes. Avoid '%abc' patterns. Partition logs by date to reduce scanned rows.
Yes. Galaxy’s AI copilot detects your database dialect and offers LIKE, ILIKE, or INSTR templates, flagging any non-sargable patterns.
Choose full-text when you need stemming, ranking, or many varied keywords. Basic LIKE queries are fine for infrequent, exact substring filters.
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