Other Databases

There is a dedicated section for PostgreSQL Support. This section provides hints and tips for generating SQL for other databases.

As a reminder, HoneySQL supports the following dialects out of the box:

• :ansi -- which is the default and provides broad support for PostgreSQL as well
• :mysql -- which includes MariaDB and Percona
• :oracle
• :sqlserver -- Microsoft SQL Server

For the most part, these dialects only change the "stropping" -- how SQL entities are quoted in the generated SQL -- but dialects can change clause order and/or add dialect-specific clauses.

This section is a work-in-progress and more hints and tips will be added over time for more databases.

Precedence

The biggest difference between database dialects tends to be precedence. MySQL actually has different precedence in the SET clause but several databases disagree on the precedence of actual "set" operations: UNION, EXCEPT, INTERSECT, etc.

HoneySQL tries to be fairly neutral in this area and follows ANSI SQL precedence. This means that some databases may have problems with complex SQL operations that combine multiple clauses with contentious precedence. In general, you can solve this using the :nest pseudo-clause in the DSL:

{:nest DSL}
;; will produce DSL wrapped in ( .. )

This should allow you to cater to various databases' precedence peculiarities.

BigQuery (Google)

Function names can be case-sensitive: you can use the "as-is" notation for SQL entities to avoid conversion to upper-case: [:'domain :ref] produces domain(ref) rather than DOMAIN(ref).

ClickHouse

This is another case-sensitive database than requires the "as-is" notation described for BigQuery above.

WITH expr AS ident is supported as a core part of the DSL, as of 2.4.962.

MySQL

When you select the :mysql dialect, the precedence of :set is changed. All the other databases get this correct.

REPLACE INTO, while specific to MySQL and SQLite, is supported as a core part of the DSL, as :replace-into, as of 2.4.969.

SQLite

Precedence of "set" operations: SQLite differs from other databases in handling compound SQL operations that use multiple UNION, EXCEPT, INTERSECT clauses. Use :nest to disambiguate your intentions. See issue #462 for some background on this.

INSERT OR IGNORE INTO: this syntax is specific to SQLite for performing upserts. However, SQLite supports the PostgreSQL-style upsert with ON CONFLICT so you can use that syntax instead, for DO NOTHING and DO UPDATE SET. In addition, INSERT OR REPLACE INTO can be written using just REPLACE INTO (see below). Issue #448 has more background on this.

REPLACE INTO, while specific to MySQL and SQLite, is supported as a core part of the DSL, as :replace-into, as of 2.4.969.