SQL Funktion Referenz
Referenz für SQL built-in Funktionen: Zeichenkette, numeric, date, aggregate, und window Funktionen.
String Functions
String functions manipulate text: UPPER/LOWER (case), LENGTH/CHAR_LENGTH (size), SUBSTRING (extraction), TRIM (whitespace removal), CONCAT or || (joining), REPLACE (substitution), POSITION/INSTR (search). Pattern matching: LIKE (simple wildcards), SIMILAR TO (regex-like), POSIX regex (~ in PostgreSQL). Padding: LPAD/RPAD. Splitting: SPLIT_PART, STRING_TO_TABLE. Encoding: ENCODE/DECODE for binary. JSON functions: JSON_EXTRACT, JSON_ARRAY, JSON_OBJECT (SQL:2016).
- SUBSTRING
- Extract portion
- CONCAT
- Join strings
- LIKE
- Pattern match
SUBSTR(s, 1, 5)CONCAT(a, b, c)% and _ wildcardsNumeric and Date Functions
Numeric: ABS, ROUND, CEIL/FLOOR, POWER/SQRT, MOD, RANDOM, GREATEST/LEAST. Trigonometric: SIN, COS, TAN, ATAN2. Date/time: CURRENT_DATE, CURRENT_TIMESTAMP, EXTRACT (field from date), DATE_ADD/DATE_SUB (dialect-specific), AGE, NOW. Date arithmetic varies by dialect (INTERVAL syntax). Formatting: TO_CHAR (PostgreSQL/Oracle), FORMAT (SQL Server), DATE_FORMAT (MySQL). Date parsing: TO_DATE, STR_TO_DATE. Timezone handling: AT TIME ZONE, CONVERT_TZ. Always use parameterized queries for computed values.
- ROUND
- Round numeric
- EXTRACT
- Date field
- timezone
- AT TIME ZONE
ROUND(x, 2)EXTRACT(YEAR FROM d)t AT TIME ZONE UTC