Sql info
Sub-divisions
| DDL Commands | DML Commands | DQL Commands | DCL Commands | DTL/TCL Commands |
|---|---|---|---|---|
| CREATE | INSERT | SELECT | GRANT | BEGIN / START TRANSACTION |
| Drop | UPDATE | REVOKE | COMMIT | |
| ALTER | DELETE | ROLLBACK | ||
| RENAME | MERGE | SAVEPOINT | ||
| TRUNCATE | RELEASE SAVEPOINT | |||
| COMMENT | SET TRANSACTION |
data-types
-in postgresql
| Numeric Types | Character Types | Date/Time Types | Boolean Type | JSON/XML Types | Other Common Types |
|---|---|---|---|---|---|
| SMALLINT (int2) | CHAR(n) | DATE | BOOLEAN | JSON | SERIAL / BIGSERIAL |
| INTEGER (int, int4) | VARCHAR(n) | TIME | JSONB | UUID | |
| BIGINT (int8) | TEXT | TIMESTAMP | XML | ARRAY | |
| DECIMAL(p,s) | TIMESTAMPTZ | BYTEA (binary data) | |||
| NUMERIC(p,s) | INTERVAL | MONEY | |||
| REAL (float4) | CIDR / INET (IP) | ||||
| DOUBLE PRECISION (float8) | HSTORE (key/value) |
Basic Definations - (External Site)
where-clause
- Where clause is used for searhing
- searching takes place in server HD
- WHERE clause is used to rescrict the rows from DB server HD to server RAM