[SQL] SQL expansion languages of mainstream databases (T-SQL, pl/sql, pl/pgsql)

Preface

Expansion of databases sql Different grammar , But it's all about Standards sql Make it more programmable on the basis of

• T-SQL Corresponding SQL Server
• PL/SQL Corresponding Oravle
• standard SQL Corresponding MySQL
• PL/PGSQL Corresponding Postgre SQL

standard SQL

The document is in English , It's a little bit too much
ISO_IEC 9075-1-2016

Structured query language , Include ：

• Data definition language (DDL), for example ：CREATE、DROP、ALTER Such statements ;
• Data manipulation language (DML), for example ：INSERT（ Insert ）、UPDATE（ modify ）、DELETE（ Delete ） sentence ;
• Data query language (DQL), for example ：SELECT sentence ;
• Data control language (DCL), for example ：GRANT、REVOKE、COMMIT、ROLLBACK Such statements

T-SQL

T-SQL namely Transact-SQL, yes SQL stay Microsoft SQL Server An enhanced version of , It is used to allow applications to interact with SQL Server The main language of communication .T-SQL Provide standards SQL Of DDL and DML function , Plus the extended function 、 System stored procedures and programming structure ( for example IF and WHILE) Make programming more flexible .

T-SQL Introduction and basic grammar

PL/SQL

PLSQL yes Procdure Language/Standards Query Language Abbreviation ,PL/SQL It's right SQL Extension of language stored procedure language . It has now become a process processing language , abbreviation PL/SQL. at present ,PL/SQL It mainly consists of two parts , One is the database engine , It's called a database PL/SQL. The second is an independent engine that can be embedded in other product tools , Also called tool PL/SQL. The two programs are very similar , Have a specific structure 、 Grammatical and logical mechanisms . in addition , Tools PL/SQL Syntax for supporting tools has also been added .

PL/SQL course

PL/PGSQL

pl/pgsql It's also a programming language , It's called process SQL Language （Procedural Language/ Postgres SQL）.pl/pgsql yes Postgresql [1] Database pair SQL Statement extension . In general SQL The use of statements adds the features of programming languages , therefore pl/pgsql It is to organize data operations and query statements in pl/pgsql In the procedural unit of code , To judge by logic 、 Loop and other operations to achieve complex functions or computational programming language .

PL/PGSQL One of the main differences from the above two is more SQL Shell(psql)

PostgreSQL Chinese document