[nongnu] elpa/emacsql 84499878d0 081/427: Add :union, :union-all, :difference, and :except.

[ELPA Syncer]

branch: elpa/emacsql
commit 84499878d0bc570d6fc3d2d9329041a41e2359ab
Author: Christopher Wellons <wellons@nullprogram.com>
Commit: Christopher Wellons <wellons@nullprogram.com>

    Add :union, :union-all, :difference, and :except.
---
 README.md  |  8 ++++++++
 emacsql.el | 12 ++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/README.md b/README.md
index 452faa7b90..7e232caa20 100644
--- a/README.md
+++ b/README.md
@@ -193,6 +193,14 @@ Provides `SET`.
 [:update people :set [(= name "Ricky") (= salary 300000)] :where ...]
 ```
 
+#### :union, :union-all, :difference, :except
+
+Provides `UNION`, `UNION ALL`, `DIFFERENCE`, and `EXCEPT`.
+
+```el
+[:select * :from sales :union :select * :from accounting]
+```
+
 ### Templates
 
 To make statement compilation faster, and to avoid making you build up
diff --git a/emacsql.el b/emacsql.el
index a3ea075d2d..4ba13c93c3 100644
--- a/emacsql.el
+++ b/emacsql.el
@@ -485,6 +485,18 @@ definitions for return from a `emacsql-defexpander'."
       (vector (mapconcat (lambda (s) (combine (emacsql--expr s))) set ", "))
       (list (combine (emacsql--expr set))))))
 
+(emacsql-defexpander :union ()
+  (list "UNION"))
+
+(emacsql-defexpander :union-all ()
+  (list "UNION ALL"))
+
+(emacsql-defexpander :intersect ()
+  (list "INTERSECT"))
+
+(emacsql-defexpander :except ()
+  (list "EXCEPT"))
+
 (provide 'emacsql)
 
 ;;; emacsql.el ends here