oracle sql concatenate rows into string

Concatenate multiple rows of records in the same column in Oracle into a string [SQL] -- raw data -- a 111 -- B 222 -- a 333 -- a 444 -- B 555 -- final result -- a 111*333*444 SELECT L4.L _ TIME, MAX (SUBSTR (L4. group CONTENT, 2) final field value

SQL queries and SQL functions　　This chapter aims　　　　Understanding Oracle Data TypesUnderstanding Data Definition Languages and data manipulation languagesUnderstanding Transaction Control Languages and Data Control languagesMastering SQL Operators

No matter whether you are a newbie to SQL, you should be a beginner in the data warehousing industry who needs to review SQL. This SQL textbook website lists commonly used SQL commands. This website contains the following parts:-SQL commands: How

See a very comprehensive SQL optimization article, in the development of the work often do not consider the performance of the lack of (at the beginning of the data volume is not seen the difference in speed). But the more you write, the more you

See a very comprehensive SQL optimization article, in the development of the work often do not consider the performance of the lack of (at the beginning of the data volume is not seen the difference in speed). But the more you write, the more you

optimization Problems of databasefirst, the question of the proposedIn the early stage of application system development, due to less development database data, the query SQL statement, complex view of the writing of the performance of the SQL

Oracle supported SQL directives can be divided into data manipulation language statements, data definition language statements, transaction control statements, session control statements, and several other types:1. Data Manipulation Language

SQL Introduction SQL supports the following categories of commands: 1. Data definition Language (DDL) 2. Data Manipulation Language (DML) 3. Transaction Control Language (TCL) 4. Data Control Language (DCL) Here are the detailed notes for these four

Read Catalogue (1) Select the most efficient table name order (valid only in the rule-based optimizer) (2) connection order in the WHERE clause (3) Avoid using ' * ' in the SELECT clause (4) Reduce the number of accesses to the database (

Read Catalogue (1) Select the most efficient table name order (valid only in the rule-based optimizer) (2) connection order in the WHERE clause (3) Avoid using ' * ' in the SELECT clause (4) Reduce the number of accesses to the database (